I feel the same. If only I could hail a taxi with an app instead of having to stand in the street and wave like an idiot at drivers that have riders but who have neglected to turn off their light (as they all do in my city.) And if only when I have to call for a cab I could give them my GPS location so they don't get lost and never show up and if I could provide my destination so they don't take the long way, either on purpose or accidentally. And if only there was a way to see that the cab was actually en route to my location and see an ETA.
If the cab industry could develop an app that works like Uber/Lyft I think they'd be competitive again. I use cabs when they're right there and I know the city, otherwise I reluctantly use Lyft or whatever's available.
Not sure what city you live in, but the ad on the top of the cab is not "the light". I can't imagine a fare system that is not hooked directly to the actual "driver is available for a fare" light, i.e., once the fare is underway, the light switches off. Also, there are apps now in several cities to hail cabs, and some cab companies have their own apps (kind of like Uber, i.e., you can't hail a Lyft or Via via Uber, so why should there be a universal app to hail any cab -- but that would depend on your city and how cabs operate).
Yes, I've tried the one app that I've seen available here (Boston) but it didn't work. It's been a few months, I'll try it again. Cab drivers here don't use their available light so that they can't be ticketed for not picking up minorities.
If the cab industry could develop an app that works like Uber/Lyft I think they'd be competitive again. I use cabs when they're right there and I know the city, otherwise I reluctantly use Lyft or whatever's available.