Basic card counting is pretty simple. I suspect most people could master it with a little practice. This is plus one for every 10, J, Q, K, and A played. Minus one for every 2-6 played. So you can gauge how favorable the deck is. This can change the odds slightly, possibly in your favor, but you are not going to get rich. I doubt casinos are concerned about this.
I have a friend who was seriously into card counting. I don't know the details, but different cards are treated differently and then how you play the hand changes based on cards remaining. I suspect this can swing the odds much more in your favor. To me, this sound exhausting and makes the game no longer a fun diversion. It is work to make money this way. By the way, he was pretty sucessfully playing blackjack and he did have concerns about being barred from casinos.