In Boston there's both a will and a way. I haven't owned a car for as long as I've lived here, and the bike lanes are so, so much better now than when I first arrived. Neighboring Cambridge now has laws on the books requiring bike lanes to be added any time that a road is rebuilt. The new light-rail extension through Somerville added a bike path alongside most of its length, connecting the paths along the downtown riverside to the Minuteman bikeway that runs 15 miles out to Bedford.
It can be done. But people have to organize and give a fuck.
[1] https://www.boston.gov/news/new-steps-reduce-vehicle-emissio...
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.
They are free on only 3 lines (plus SL1 leaving the airport) https://www.boston.gov/news/mayor-wu-takes-steps-expand-fare...
https://pedestrianobservations.com/2021/07/23/the-leakage-pr...
So it's not as simple as take the bus. (Which doesn't exist.) But that's fine. I mostly just don't go in.
The bike lanes mentioned above all, by physical necessity, come at the expense of cars, either by reducing parking lanes or reducing driving lanes. Even if there were the same amount of traffic, fewer cars would be on the road because there is less road to be on.
Not even the best transit cities have transit every 5 minutes all over the city. There is a lot of room to improve in them all
The easiest way to do that is reduce commuting trips, as those are very common, but you can reduce trips in other ways, such as allowing more gas stations/convenience stores. If it's a five minute drive to the grocery store but a two minute walk to a 7-11, some of those trips to the grocery store will be replaced with walks to the 7-11.