So the only way to know that this has been done is to read the OBD2 VIN or check all the resaleable parts for VINs?

It sounds like this scam would only get discovered when you go to the dealer for service, perhaps.

Yes and no. In a video I watched on YouTube the people fencing the car had scratched off VINs in the bonnet, door and windscreen, painted and re-etched the exported car's VIN and gone out of their way to find a reasonable fake V5 certificate (UK equivalent of a DMV cert I think) with similar specification as the stolen car (or found the docs first).

The car was sold on, eventually went to Copart with a blown engine and then the YouTuber found out through his videos that the car he owned was stolen and the original had been exported because the interior color was not the same as the decoded VIN. Only when he took the engine out of the car and compared the engine number with the one in BMW's database and the reported VIN in the infotainment was he confident that the car was stolen, same for Copart (who wouldn't entertain the car was stolen).

I think if it wasn't a famous YouTuber who bought the car, it's highly possible that the stolen car would go nu-noticed throughout its lifetime as stolen, even if taken to a main dealer. If I recall correctly the car reports he used (maybe car-vertical) also didn't pick up any discrepancy.

For the criminals its good business, you find a 30k plus car, pay for a clean VIN from cypress or somewhere and then do the damage to the car to re-new it as a different car, even if it costs 10k to do, its a lucrative 20k "profit" and thats on the high end, seems like cars can be stolen overnight, especially ones the criminals specialize in.

edit: https://www.youtube.com/watch?v=RI4S2LT_ntE