For one, cars old enough to be without emissions or safety equipment are becoming more rare, to the point that they are now worth a significant amount of money. Anything that is currently in that grey, "pre-classic" area is already a very complicated machine that is very hard to maintain without OEM spares and support. Anything newer is designed from the ground up to hit a specified lifetime then get ground up into flakes for recycling. Opinions vary on the positive outcomes of this.
For two - regulations are constantly changing. Many cities have low-emissions zones. The EU is making significant changes to their vehicle end-of-life laws.
"Poor people" are not going to be maintaing classic old cars as a cheap form of transport, like some rose-tinted view of Cuba. They already lease brand-new cars.