A lot of these jobs that they're bemoaning the loss of tips for, also aren't all that necessary. If establishments want to give off the impression they're upper class, they ought to pay these "professions" considerably more considering they obviously have the money. Otherwise, opening doors and operating elevators are things I'm content to do on my own.
The ostensible purpose of the doorman is to add a layer of security. Someone who is always there watching, looking for people who don't belong, receiving packages and securing them, etc. They are basically a crime deterrent. So is the elevator operator to an extent (although that one is really more just for impression of being fancy).
Sounds like a pretty important job. I imagine a building would want to compensate such a person pretty well in order to help keep the building secure and functioning smoothly. As they say, you get what you pay for.