American here. Filing suit for a taxi that never showed is a bit much but having been in that position I can understand the anger. Sometimes it's necessary to read "sue" as an American idiom for "Grrrr, I'm really mad and they should have done better."
That said, these crazy new-fangled smartphone app taxi services show me exactly who's coming to pick me up and how far away they are. That's a big step up from "we'll send someone as soon as they're available".
Voting with your dollars (euros, whatever) and putting them towards a better service will ultimately make a big difference. But, wait! Are you going to find another company to provide a taxi or file a complaint with regulators (generally run by livery companies in the US) (it's a problem, we know) while you're waiting for that cab who's taken another fare and won't be coming to pick you up after all?
It's probably best not to think of uber, sidecar, lyft, etcetera as taxi companies. They're providing a marketplace for that kind of service. Folks that don't play nice (cabbies who don't show and customers too drunk to sit without vomiting) get weeded out.