There is a car that fits any size.I don’t even know what you’re trying to say. Yes, Disney used to be really great at designing inclusive ride vehicles. That stopped. As you point out here, FoP, 7D, and Tron are much more restrictive. That’s the issue. The fact that, say, Thunder or Pirates is very accommodating has no bearing whatsoever on Tron.
As to the back seats… in all seriousness, what makes Tron exceptional, or even interesting, beyond the restrictive seating position? This is the entire attractions fundamental flaw - it offers very, very little beyond the seating.
Perhaps it's time for a portion of the population to take a look at themselves and make some changes.
It would make getting around the parks - the on foot portions - much easier as well.