You could also ask, "Why is pool popular in bars? "
The reason, in both cases, is that both games are slow. At a bar you're probably drunk so any reflex game is a waste of time. They also tend to be loud and obnoxious. Golden Tee is pleasant and you don't even need volume to play it. If your drunk buddy is hitting on a chick, you have a few moments to grab him so he can take his turn. He won't get crushed by a mushroom falling on his head or anything. Plus, it's a generic game that most people can figure out. You simply roll the trackball towards the hole. Any sort of knowledge or skill about the game can come later. It's a big time waster, and it's social. So a game like Solitaire wouldn't float because it's not social.
Simple, casual, social. = Big success in bars across America.