That'd be great, but no one wants to actually build any workable alternatives, at least in the US. A lot of people would probably be happy to give up their car

That'd be great, but no one wants to actually build any workable alternatives, at least in the US. A lot of people would probably be happy to give up their cars (or at least keep them parked until they need them for weekend trips) if they had good public transit available to use instead. But US cities are not doing a very good job with that.