While I agree that no job should REQUIRE a tip, there are card rooms out there that would not even be open if they had to pay the dealers $20 an hour, just as many many restaurants would not be open if the wait staff had to be paid minimum wage or more.
With that there is the fact that the good dealers will go where the money is, just like workers at any job. If you dont tip your regular dealers then they will leave and work somewhere else, then you are left with crappy dealers and I bet players wouldnt like that at all.
As for the casinos, well they are money hungry, and if the room doesnt make a profit standing alone they will close it and the poker will be gone.
The only alternative to tipping is higher rakes at most places, and then the players will leave and go somewhere else, then the room closes, and no one wants that.
I like the idea of tipping out at the end of a session if you have had a winning night, however, some of the dealers that dealt to you may be gone for the night already by the time you are done, then they are left out. We have players that will return the next day to hit up the dealers they missed, if you would do this then excellent, if not then you miss some people and the problems above all come into play.
As far as casinos in other countries, well they have other things at play to be able to pay their dealers more, but here in the good old USA, no side wants to give - players dont want higher rakes, more costly food and drinks, and the casino execs dont want to give up their fat pay checks, so tipping is the only way to keep the good dealers around.
If your dealer sucks, then well do the same as you would if any service job worker sucked, but you should keep consistent. i know people that will still tip a waitress if she sucked just not as much, treat your dealers the same if you do this.