The medallion system was completely broken before the ride apps appeared. Traditional car services were reliable and easy to reach via phone. A lot of them have still survived.
It's more expensive but I always use a traditional car service to get to the airport. Super-reliable, comfortable, clean, good drivers. They're always pre-scheduled (which is fine for the airport) but I've never had problems with getting them to make changes when flight stuff happens.
Why would it be any different from auto/auto part supply chains in general? (Which, yes, from personal experience are a considerable issue at the moment.)
There are plenty of other vehicles. Yes, the limo companies liked the unibody limos but there's no shortage of different models they can use. I'm certainly not especially picky in general.
In Vancouver BC where petrol costs have always been considerably higher than the other side of the border in WA, taxis switched almost entirely to Prius as far back as 2004. Even before that it was very common to see CNG modified taxis.
