I use to be pretty hardcore into blackjack, but it came to the point where it wasn't fun. I got into during the end of high school (way before the Bringing Down the House Movie came out) and practiced and practiced. Counting down decks, estimate how many decks left in the shoe, and all the other indices (how basic strategy changes depending on the count).
All that to just put the game in your favor very very slightly. What most people could could make (long term) playing 8 hrs a day is less than my job pays me. Depending on variance and how the game is still only slightly in your favor you would need a huge bankroll to really survive long term with the huge swings.
If you play with $25s and above they will immediately boot you if they see you using "advanced tactics" or worse yet, tell you have to flat bet (can't change your bet) or just tell you that you are too skilled for their game and to please try one of their other excellent tables games (meaning you can't play BJ there anymore). Wonging (standing behind a table and counting the count is strongly in your favor) also gets you bounced after a few attempts. Pit Bosses and dealers all know how to count and tell if someone up to something, and the only way to avoid any heat would be to play nearly as bad as a normal person. Oh yeah, now with automatic shuffling machines at certain places there is no point. For anyone interested in learning though, there are a few forums that specialize in it and many different programs to help teach people practice and to run simulations with expected variance, etc.