In my opinion, card counting is applicable to online and physical casinos. I think iit works better in online casinos because there is nothing the house can do. There are other solutions and the solutions above are applicable mostly in physical casinos.
Do you seriously say that? Have you ever played blackjack in live casinos? Well, I'll still explain.
First of all, in live casinos, they play with 8 decks in the shoe. From these eight decks, only four plays. So, from 416 cards, approximately 208 plays and sometimes it happens like even less or more, it depends on the shuffler. Card shuffle quality is controlled, so, for this reason, shufflers try to put the cutting card in the front and not back to the middle. It results in playing even fewer cards, nearly 170-200. So this action even lessens your chance to count cards. It has zero idea to count cards in live blackjack. Also, there are risk analysts there who sit and have a look at players behaviours. Not only that, shuffle quality is always monitored and if it happened like shuffle quality in the certain round is very, very low, then the game can be cancelled and players get refunded.