Very different places. Different population density and population movement dynamics. Miami has, for example, next to no public transportation. In contrast, you can't live in Manhattan without using it. And clearly they had very different shocks to deal with.
BTW the Sun newspaper is better known for its topless pg 3 girls than the quality of its reporting...
EDIT: as for antibody testing, Miami-Dade and Broward county combined have conducted swab tests equivalent to a mere 3.5% of population. Those are static tests with negative results only valid as at the time of the test. Just under 12% tested positive. (I had to pass by one of the testing stations (Marlins Park) the day before yesterday. Traffic for a drive-through test was queued up for miles.)
I don't think it's even possible to get an antibody test even if you were prepared to pay for one. The UK has yet to source reliable antibody testing equipment. So I haven't heard of a lot of reliable data regarding population infection ratios. Guesstimates for the UK are still sub 10%. Even Sweden's state epidemiologist, where they've largely 'let her rip' speculates that the most populous cities of Sweden such as Stockholm will only achieve 40% immunity by the end of May.
Judging from friends in the UK who have had this virus - most were absolutely flattened and bed-ridden for between 3 and 5 weeks - it's an extraordinarily optimistic over 40-year old who thinks they've had COVID-19 without suffering significantly noticeable symptoms. 76.8% of respondents in this forum's demographic profile poll were 50 and over; 49% 60 and over...
However the people in NY didn't get the virus from the subway. 66% got it while sheltering in place at home and then what 18% got it in nursing homes? Most infections that had symptoms severe enough for people to get tested did not happen to people out and about.
Regardless, the more important measures are deaths and hospitalizations, not infections. Infection rates will increase as testing expands. Probably by a lot.
I reject argument from authority. Most all newspapers and news magazines are little more than partisan rags these days. The Sun quotes data from East Anglia University, and it's likely they are giving actual numbers.
To avoid falling into the lazy logical fallacy of "argument from authority," we must evaluate the actual data and not ascribe any more or less credibility to it based on the source. The "experts" have been so wrong so much throughout this crisis that we MUST evaluate all into using data and logic.