specific enthusiast forums. An hour of researching there and you'll know pretty much every major (and most minor) issues that will creep up on a platform over 20 years and 300k miles.
Problem is, you have to get enthusiast owners who have driven them 300k miles before those reports start rolling in.
So with new platforms and new vehicles, you are essentially rolling the dice.
As much crap as Toyota gets for never updating their vehicles, it is pretty nice to go to the forum and figure out what issues owners have had with their 2010 GX460 over the course of 250k miles, and then go to the dealership and buy the same vehicle new in 2023 and now exactly what to expect over the next decade of ownership (if not have most of those issues from 2010 already corrected on your model).