I suspect that it might not be JUST the timing belt that causes people to ditch their car.
To the contrary, I think it's perception:
Look at me, I bought a Honda - I expect bulletproof reliability. People still drive Civics from the 1980s! They must be indestructible!
...wait, why is my car making weird sounds? Mechanic?!?!?! "Sir, you need to replace your timing belt. It'll be $1,200." If my 'bulletproof' car is going to have expensive repairs like this, then it must be a lemon or Honda's reliability has dropped.
it, I want a new car now and want to offload my nightmare of a car before it costs me more!
My parents were like that with our RX400h. The driver's side mirror motor (one of two - it moves side-to-side, but not up-and-down) is LITERALLY the only issue we have had in 9 years and 90,000mi. The quote to fix it was $750 and my mother said, "well, sh!t...if that's what it costs to fix things on this car, it's time to get a new one before we start getting MAJOR repair bills!"