I think the problem is that there are 2 different types of "can't": can't as in technologically impossible, and can't as in legally disallowed.
In the past, the former was usually the case. Vendors literally could not technologically take away features because things either were not controlled by software or software could not tell the hardware apart because there were no unique identifiers. Because of this nobody really pushed for the legal protections, and as such they do not exist today (at best you _might_ be able to claim misrepresentation by the previous owner and get a return or refund, like if someone sells a LHR card as if it were non-LHR. But with a large purchase like a car, that would be costly time and money wise).
> Tesla should not have been able to do this, period.
Yeah, morally, but we need to start working to make this guaranteed legally. As it is now, "Nvidia sends me a 3080Ti as a replacement (because maybe they don't have any 3080 in stock) then no, they can't lock it down to 3080 level 3 years later with a software update" is totally allowed.
Heck, they could even cut down all legitimate 3080Tis to what would be 3080 or even 1060 performance via drivers after 3 years and you'd be able to do nothing besides complain on social media -- you still have exactly the amount of hardware sold, and they never promised any performance levels (just check their site, you only get things like compute units, clock speed, ram etc. not performance guarantees like FLOPs or FPS)