I had two incidents in the UK recently where my app of choice failed me and I was quickly bailed out cheaper by googling "taxi $TOWN" and having a one minute conversation with an operator.
The main amazing thing about Uber is that you can go most places in the world, not know what you're doing with obscure public transport/payments/etc and just get an Uber to your hotel, no problems. It's so, so much better than what came before.
The apps did three things that the call services did not do:
1) subsidize drivers with vc money for many years making drivers plentiful and fares cheap
2) use unlicensed cabs so they could saturate areas like Manhattan that had previously limited the amount of cabs that could operate
3) Deprive drivers of info they might use to reject fares they don't want (like destination).
Not remotely my experience in Chicago, and I lived in a relatively primary service area (Wicker Park). Calling them was basically pointless, you needed to walk to a cab stand and hope there was a cab standing by if you needed to go to the airport at a weird off-peak time.
And my friends all had similar experiences to mine as well. It was a trope that you'd call dispatch and schedule a ride, and then maybe it would show up within 90 minutes of the actual time assigned. You could even listen to the dispatch radio and realize how much of a shitshow it was with cabbies assigned to a pickup ditching it for a street fare randomly. And how little dispatch cared about it all.
Uber was a night and day overnight change for the better.
The only "good" cab experiences were flag pulls from the street within short city trips. Usually the loop to back home during peak after-work or bar traffic times. Anything else was frustrating to outright unusable.
This is mostly a problem with the people you pay taxes to who would invent systems to restrict the driver numbers.