Next time you take a drive, count the fraction of cars on the road that are >= 7 years old. Now imagine those cars are the only ICE vehicles on the road and everything newer is electric. Consider what’s that fraction, how much disposable cash do you think those folks will have, and how many inexpensive gas stations and mechanics will continue to stay in business to support those people?
Depends on the definition of "working". Modern cars are full of components that unexpectedly cost $thousands to replace. I prefer to replace my family's cars when the manufacturer's warranty expires, having been caught out a few times now with stupid repair bills for 4-8 year old cars.
But if the car is likely to plunge in value, I might choose to move faster to offload it. People will either do that or keep it until it dies. Enthusiastic countries will accelerate the process by increasing taxes on older vehicles.
