The demand for second hand cars is already there. In 2030 people aren't going to turn around and say "wow hmm I all of a sudden want a second hand combustion engine car" and find themselves priced out. The first people to be priced out will be the price who buy cars 2-3 years old and drive them until they need a major repair. Realistically, there's 20 years before the full impact of this policy will be felt at the bottom of the used car market, and the "poor" (who are a large group) will be hit by this law. That means there is 20 years to come up with an incentive or a solve.
It's easy to dismiss progress with a one line snarky quip on the internet, and this is a hugely positive move.