If the game of blackjack can really be beaten, why is blackjack still offered by casinos?

Blackjack can be Beaten :

Blackjack can be beaten but for every smart player there are many undisciplined players that don't play well enough to win.

Land based casinos tolerate low wagering card counters as an expense of running their business. There are also a lot of bad card counters out there that lose money. When the first card counting books were written, the profits of casinos actually grew as hoards of new players flocked to the casinos.

In online blackjack, the casinos count on the fact that many players are not disciplined enough to follow basic strategy or to stop playing. As proof that the game of blackjack is beatable, many online casinos do not provide welcome bonuses for blackjack play.