The "gradual" part is hard because so many changes need to happen at once for a lot of these things to be feasible. Being able to get halfway to where I'm going affects me the same way as not being able to get there at all.
If you try to limit cars without adding better last-mile options (especially in the U.S. where huge portions of the population don't regularly walk even one mile at a time), people can't get anywhere, but if you try to roll out last-mile options without limiting cars, people either don't use them because they can still use cars, or they get hit by cars.
Add to that that everyone seems to feel time-crunched as it is (who do you know who feels like they're getting enough rest and doesn't describe themselves as "busy" any time you ask how things have been?), and the switch from "I could cover a mile in 2 minutes at 30mph vs. 20 mins at 3mph" and no one wants to change.
If you try to limit cars without adding better last-mile options (especially in the U.S. where huge portions of the population don't regularly walk even one mile at a time), people can't get anywhere, but if you try to roll out last-mile options without limiting cars, people either don't use them because they can still use cars, or they get hit by cars.
Add to that that everyone seems to feel time-crunched as it is (who do you know who feels like they're getting enough rest and doesn't describe themselves as "busy" any time you ask how things have been?), and the switch from "I could cover a mile in 2 minutes at 30mph vs. 20 mins at 3mph" and no one wants to change.