It pains me, but when it comes to taxi drivers, I have to agree with Saz. The majority are frankly useless, they provide awful service, drive erratically and unsafely, and do whatever they can to get a buck out of you - and then usually don't even say thank you for the tip, which they don't deserve but lucky for them I'm not an asshole.
The good taxi drivers will always have a place in society (well, until we go driverless, but that's desirable on many levels). Nothing beats being treated to a good, clean car, driven by a respectable person who goes out of their way to provide everything you might need. The level of service they provide simply cannot be replaced by a machine. For instance my car was in the shop not long ago (September I believe) so my wife had to take a cab to the grocery store. He picked her up on time, dropped her off, opened and closed the door for her, and gave her his cell number so she could call him when she was just about done shopping. Then he helped her load the car, took her back to our place, and then refused to let her carry all the groceries on her own. So he carried them to the front porch for her.
There will always be people willing to pay premium money for that level of service, and I'm one of them. Uber can take over, the shitty drivers can move to them, and the good cabbies can make a good living working for niche companies that provide stellar, exceptional service.