Not disagreeing with you, but more comes into it than that. Back to my post a bit...brass life is relative to how hot it's loaded and the support around the case. For example..222's used to be popular in BR, and got good brass life with quality brass and sizing techniques. But, typical loading pressures were less than is typical in BR cartridges of today and there's more barrel support around a smaller diameter case. Neck sizing only, was popular with this cartridge in it's hay day. FWIW.
There's more too getting 50 firings from a piece of brass than just buying Lapua. Pressure always matters, as does how much the brass is worked. Agreed..neck sizing only, does work the brass less..but if all it ever did was expand to static chamber dimensions then spring back...it'd never get tight anywhere. In reality, we know that's not the case.
But, barrels expand upon firing and the brass follows suit. In fact, that's exactly how a Pressure Trace system works. It uses strain gauges that measure barrel stretch and converts it to current and then to a graph you can see on a computer. You can literally see primer ignition and muzzle pressures, which are of course much, much lower than peak pressures. Without some shrinkage of the brass from it's maximum expansion, eventually, it will get tight. Remember this...a 1.000" peg does not fit a 1.000" hole...they are the SAME. There must be clearance for a given peg to freely fit into a given hole.
That's why I full length size...minimally.
I agree with everything you say. It has been my experience that if a round expands a chamber enough that the brass cannot spring back there is excessive pressure involved for that gun and that load or the brass was too soft for whatever reason.
Now I have to back up a little here and remind folks that this is my experience - one man's experience - someone else may have different experience. There are a lot of different things that can contribute to what happen when you pull the trigger. If I was to get a sticky case I would full length size the brass and drop the load a bit and then go back to neck sizing. That has never happened to me in over thirty five years (I have been loading for 48 years so I made a few mistakes in the first few years). When I say what I say it deals only with the way I reload for my guns and you may have a different experience. The goal is to give you alternatives that you can try while remaining safe. If you get excessive case growth when neck sizing the try partial full sizing - sort of half sizing with a full size die. Reloading is about trying new things safely to see if they work for you.
Every gun is different and every reloader is an individual. If you try something and it causes problems then don't use it go on to something else.