It's interesting re US-trained PPLs.
I know two groups of US-trained pilots.
a) Those that did their whole PPL/IR there (nearly all people I know with a current PPL/IR did it in the USA). These all fly, and fly a lot, some do 500hrs/year.
b) Those that did just the PPL there. Most of those have stopped flying.
I would guess that in group b) one gets two sorts:
b1) Those that go to the USA because it is cheaper
b2) The remainder
I bet that b1 drop out quickly, while b2 hang in there. The cost saving (a few k at most) is insignificant in the longer term.