Are VINs not tied to the make, model, and year?

Ultimately they are tied to an individual vehicle in its original configuration in every way.

But thieves don't really really care about what it technically represents, they are more interested in what they can get away with. That would be solely dependent on how stringent the inspection is to get a rebuilt title.

Sure, but that's not that hard to find a match of. And if you cover all your bases, you can probably get away with a year or two plus or minus in most cases.