You're assuming that people who take Uber would take taxis if Uber were not available. That's a big assumption.
I (like most people, I'd imagine) evaluation my options for each trip:
- Drive for myself. Fast, comfortable, fun, probably a trivial amount of gas, but I refuse to search for street parking and depending on destination I may not want to pay $30+ for a garage space.
- Taxis, which will probably run $25-30 each way + tip, for around $70 spent on transportation for the evening.
- Cycling, which is a no-go in Chicago winter, or when I'm going somewhere nice and don't want to arrive sweaty, or when I'm going home late and don't trust the safety of the bike path.
- Public transit, which will be cheap but excruciatingly slow and a revolting experience on hard surfaces in a harsh florescent-lit car smelling urine, listening to ambient rap music from people's shitty phone speakers, and trying to find something to look at other than the people my seat is pointed at.
- UberX, which is fast but a tad expensive for me at ~$15 for a taxi-like experience (except you can actually get one in my neighborhood).
- UberPOOL, which is usually a "just right" balance of comfort (sit in a nice or at least modern car, look out the window, other passengers are rarely if ever an issue), speed (the routing algorithm does do ridiculous things, but rarely), and cost - usually around $7-$10.
- Not go out because I don't want to put up with public transit or spend what it costs for private transit.
Withdrawing Uber won't put me in a taxi, it'll put me in my own car, occasionally public transit, or more likely staying in and ordering delivery.
Same with Airbnb. I take longer vacations, or vacations I wouldn't have in a hotel, because Airbnb is cheaper. I don't have extra money lying to pay hotel prices; if the cost of travel increases I will buy less travel.