I would say that by now any and all effects from 21 have been wiped out. Right after the movie was released on DVD, there were a ton of people playing thinking they could count. What it did do was make a ton of money for the casino at the time, because few to none of these players had put in the time it takes to learn BS, learn a counting system, and learn a bankroll management system. Though it did help the AP's at the time, because the new "counters" were for the most part a joke and the casinos thought almost anyone doing something that resembled counting was another hack that had seen 21 (cover is cover, I won't knock it).
Though I will say, I liked the movie for entertainment value only, same as I like most movies that deal with gambling, and it always gives me the impulse to go sit at the felt after I watch it.