I live in Amsterdam which is arguably a few decades ahead in this process. It is both true that something can be done but also that we are nowhere close to actually closing this issue.
I don't mean to discourage people from switching where and when they can (or give anybody an excuse not to). There are tangible quality of life benefits that can be obtained each step along the way. So if car usage drops, say, from 90% to 60% thats hugely important.
But structural changes in the layout of urban environments are a wicked problem that will keep people busy (and procrastinating) for a long time.