Going back to the OP's question, Hodgdon has never made the powders sold under its name. B.E. (Bruce) Hodgdon started the Hodgdon Powder Co. up by buying surplus DuPont and Winchester-Western made stocks at the end of WW2 when ammunition manufacture was drastically scaled back leaving vast stockpiles of propellants in the manufacturing-supply chain. He'd learned that the same situation applied at the end of WW1 and thousands of tons of powder had ended up being destroyed. The original H4895 was .30-06 M2 ball ammo powder, H4831 was from heavy machine-gun or light cannon ammo production, the forerunner of BL-C(2) was called Ball Lot-C and came from demilling millions of W-W manufactured .303 Brit rounds that were being supplied to us Brits.
When the surplus supplies ran out in the 50s, early 60s, Hodgdon looked for suppliers to make similar grades and most stick powders were originally made our side of the Atlantic by ICI Nobel at Ardeer, Scotland. Ball powders were supplied by the Olin Corporation who made Winchester ammo and propellants and some Hodgdon / Winchester grades are close if not identical. W760 and H414 are the same thing in different bottles, while W748 and H. BL-C(2) are close but not the same. Three generations of the Hodgdon family have become adept at making contacts within the large manufacturing outfits and adapting propellants designed for other purposes to handloaders' needs and adapted to use in a huge range of commercial cartridges. In doing so, they've also become wholsalers and suppliers to many ammunition manufacturers acting as the link between the original factory and industrial users, so it's not just us they supply.
ICI Ardeer closed down in the '90s and Hodgdon moved its extruded powder supply to the privatised former government ADI (Australian Defence Industries) propellant plant at Mulwala, New South Wales. ADI has since been bought by the multinational defence supplies group Thales.
So .... why isn't VarGet made in the US? First of all you guys didn't develop it. You might as well ask why Rolls Royce cars or Barbour jackets aren't made there, or for that matter Vihtavuori powders.
But, there are deeper reasons too to do with the nature of explosives manufacturing and defence industry ownership. The place that makes Pyrodex aside, the US has only one propellants factory left - the former Olin Corp ball powder maker, now called St. Marks Powder Co. near the the town of St. Marks FLA. Like every other significant powder manufacturer it's one cog in a multinational's operation. in this case General Dynamics Ordnance division.
St. Marks makes all Hodgdon's 'spherical' grade powders including some pistol grades like Titegroup that you might not think of as 'ball'. St. Marks has a good steady base operation in that it has supplied the majority of propellants to Uncle Sam for his smallarms ammo for over half a century. When the US adopted the 7.62mm M80 in the 1950s, it took a decision to only use ball powders, and that applies today right through the 5.56mm era, even though the former DuPont corporation developed the propellants for the original .223 Rem / 5.56mm and the AR-15 was built around the pressures they produced.
All Hodgdon extruded powders come from Thales / ADI in Australia and the partnership has worked out VERY well for all parties. The Hogdon range has doubled - at least! - since I started handloading, and the pair have been very innovative in improving powder characteristics and behaviours, such as the Xtreme temperature tolerance. BUT ... remember that handloaders are small beer to propellants manufacturers whose main business is supplying powders in bulk to the ammunition manufacturers, especially for military orders. Moreover, 'canister powders' mean a lot of extra work and expense to the manufacturer, packager / distributor as (unlike the bulk commercial orders) the burning characteristics must be kept the same or close from lot to lot if necessary by blending the outputs of different factory production lots. 1lb / 8lb packaging and the high costs of distributing small quantities of hazardous materials add enormously to workloads and costs.
Finally though, there is the SAFETY aspect. Nobody makes extruded (stick) powders in the US and haven't done so for many years, likewise the UK and many other western countries. IMR powders are mostly made in Canada, Alliant rifle powders in either Sweden (Bofors) or Switzerland (Nitro-Chemie). Many old plants went back to WW1 were out of date, but worse built close to villages and towns that expanded throughout the 20th century until their suburbs ran up to the explosive factories' boundaries. As safety rules were tightened, it was deemed totally inappropriate to have people living so close to dangerous manufacturing activities - the houses didn't go, the manufacturers did!
Then ... ball powder manufacture is inherently safe until its final stages when the little balls are precipitated out of a solution in a still. Until that point, the ingredients are made up in non-inflammable, non-explosive water based slurries and piped from one process to another. Extruded powders on the other hand start out by nitrating wood or cotton fibres producing 'guncotton' a fierce, unstable, and violent explosive. The remainder of the processes involve altering the explosive's chemical structure and burning characteristics by adding and extracting solvents or other inflammable / explosive agents which are themselves dangerous. The result is that this type of powder is more expensive and dangerous to make, and modern health and safety rules virtually rule out its manufacture in many countries. A contact in the US powder business once told me that your EPA requirements on making such powders haven't banned it, just made it so expensive and restrictive that you'd never sell a pound of US made extruded powder.
There is a final, and VERY important factor. Powders were mostly made in government plants outside of the US, and even here they were made by two or three large combines (primarily Olin and DuPont) who were very close to the military procurement people. Since the 1980s, all western governments have got out of the arms manufacturing business and where private suppliers were previously used moved to much more distant arm-length arrangements with completely open tendering etc. The view is that 'the free market will supply the best deal'. The trouble is that demand changes dramatically in this field from year to year depending on whether you're fighting a war of not, and private companies won't keep large amounts of spare capacity standing by for purely 'strategic reasons'. This is a major reason for the periodic serious shortages of some components over the last 20 years, especially primers. Right now, government demand is on the way down as the UK, USA, and NATO pull out of Afghanistan and Iraq so supplies should be plentiful, but they're not for two reasons.
First, ammunition manufacturing capacity has been reduced too much by private companies (or not increased enough to take the place of closed government factories), hence the recent Bulletin story about Remington Arms' huge expansion of its Lonoke AR facility. Second, and more important, the panic buying and hoarding that's going on after the Sandy Hook school shootings. This is the second such event in recent years, the first being fears that the newly elected President Barak Obama would introduce gun ownership and handloading controls after his initial inauguration four/five years ago. No suppliers irrespective of where they're situated, whether in downtown Burbank or Outer Mongolia could cope with the panicked demand that good old American Joe Shooting Public has created here out of his/her own fears. Here's what the Forum Boss wrote after speaking to major suppliers Brunos recently:
http://forum.accurateshooter.com/index.php?topic=3812995.0