On Friday I observed how for a trip from New York to Washington, DC, there are a variety of transit options, from Chinatown bus up to chartered limo or helicopter. This variety allows you to pick an option to match your budget. A small increase or decrease in your spending power translates into a small change in your comfort and/or convenience. Tune in to this week's Thinking Allowed for a fascinating history of this phenomenon on the London Underground.
Now let's contrast this with commuting from the Bronx to East Midtown. You can have a nearly free commute by bike, or a cheap commute by subway or local bus. But let's say you're a little better off, and you can afford the express bus or Metro-North train, where you almost always get a seat.
Now you get a small windfall, and you can afford a little nicer commute. There's nothing that's a "little nicer." You can take taxis, but you'll probably blow all that windfall in a couple of months. Your windfall isn't enough to get across the "Death Valley of Commute Options."
Suppose on the other hand that you get a promotion, and you know you're going to have a bigger salary for years. You can afford a down payment on a car, and get to work that way. Congratulations, you've made it across Death Valley!
But then the economy tanks, you get laid off, and you have to take a lower salary. You can't afford to pay for gas or park the car in Manhattan any more. You could take taxis, but you're probably better off saving that money for something else. You have to trek back across Death Valley and ride the express bus again.
Now imagine that you live in a part of Brooklyn, Queens or Staten Island, or even Manhattan, where there are no express buses or commuter rail stations. Your choices are subway or car, with nothing in between. The valley is even bigger.