Wait: downtowns are dying all across the country, and you want to solve that problem by charging people more money to go there?
Some of these cities are now beyond repair, not least for the overarching national trend of capital concentration in Silicon Valley/Silicon Alley, but these reforms would still help enormously. For example, Bloomberg's plan to toll bridges into New York City that was vetoed by car-dependent Albany. It's absolutely ridiculous that exurban commuters are allowed to devastate NYC every day, for free, because they're too entitled either to live in the city or even to commute via less destructive trains.
I would really love to hear your explanation why New York City should be required to spend billions on bridges and roads crushed by automobile traffic for commuters who don't even pay taxes into the repair fund. Much less why NYC residents should be forced to give up enormous swaths of precious road real estate at peril to their health and quality of life.
They don't. They can stop doing it any time they want.
I don't think the result is going to be what you expect, though, especially now that no one has to live (or even visit) the city to do most types of business.
That said... if someone wants to live in exurbia, he should pay an appropriate amount to access amenities downtown. It's absurd that someone can pay $1500/month for a studio downtown, but only a few feet from his front door, anyone can drive a similarly-sized vehicle at hazardous speeds for free.
Driving is essentially free in the US, despite enormous costs in terms of infrastructure and public space. That needs to change. If car-dependent exurbs must continue to exist, then we should at least make those exurbs responsible for their own costs rather than forcing urban residents to have their neighborhoods destroyed and then pay for the privilege.