When I drove days, I hung out at the hotels quite often. When I drove nights, I ran the bar circuit. There, the trips were small, but they were over and over and over with people bar hopping. Back in the early 1990s, for instance, on a Friday night at peak bar times, there's no point hanging out at the Southland Mall (before there were many bars in the south end), nor was there much point in sitting at Superstore at 4:00 a.m., or sitting in front of a nightclub at 10:00 a.m. Monday. Yep, the cabbies will hang where the trips are likely.
Back in my driving days, too, the hotels were usually very well covered for morning trips to the airport and so forth. There would rarely be a difficulty getting a cab there unless it were -40 or something like that, which would bleed off a lot of cabs for more "casual" customers.
qwerty: Yes, GPS is no replacement for a map and actually learning the city. Anyone can follow a GPS and likely get where they're going, but they're not usually putting a lot of thought into it. As for unprofessional, there are some "unique" cabbies out there, to say the least. Some care, some don't. I don't have any evidence that it's getting better, unfortunately, and that is helping the competition.
And I know exactly what you mean when you say you feel less like an alcoholic going out to the bars. After all, anyone will say that the guy who drinks by himself at home is an alcoholic. So, I avoided that as long as I could, too.