It’s true that the vast majority of professional gamblers are poker players and sports bettors.
However, it is possible to make a substantial income at blackjack. If you’re happy with an income of, say, $25,000 a year, it’s easy. If you want to make more than that, it’s very hard, because the casinos focus their card counter detection efforts at higher limit players who can really hurt them. If you want to bet $5-$25, and are polite, they’ll leave you alone even if they know what you’re doing. In most casinos, anyway. I wouldn’t try it in the smaller ones that are sweating their action, but at Caesar’s palace their floorman has more important things to do than try to bust some young guy who’s pulling $8/hr off their blackjack tables. Especially since most of the young guys who are trying to do this are probably losers anyway, so the whole population of people trying to do it are probably a wash anyway, and good advertising.
The guys the casinos are afraid of are the big limit counters betting $100/hand and up, and the professional teams with bankrolls in the millions of dollars who can swoop down on a casino and take them for tens of thousands.
Even so, there are a handful of people still making over $100,000 a year playing blackjack. How do they stay undetected? By camouflaging their play, and by adopting a ‘hit and run’ strategy. They’ll play until they get a shoe with a count that requires them to spread their bets a lot, then if they win some money they pick up their chips and leave before the casino can spot any patterns in their play.
This is a tough road to go down. Moving from casino to casino takes a lot of time and effort that returns nothing. These guys will play Vegas for a few weeks, then go on the road to regional casinos, Atlantic city, etc. Always travelling, living out of suitcases, etc. And when they do get caught, the casinos share their information, and these guys can have their careers ended overnight. And even the best of them are gaining maybe a 1% edge over the house, which means in any given year their income can fluctuate wildly. Not for the squeamish.
But the blackjack teams are a different story. There are a few teams around that have been in existence for decades. They have spotters, accountants, you name it. A member finds a casino with a good game, and alerts the team. The members are often professionals in other fields, and they’ll take a few days’ holidays from the jobs and fly in to the casino and play BIG money. The team pools their bankrolls, and each player can play as if he owned the whole bankrolls. So they play huge. And they have sophisticated ways to avoid being spotted, such as using the ‘big player’ technique - the counter sits at the table flat-betting, and when the shoe composition favors the player, he’ll signal the ‘big player’ to come in and put down a huge bet. If the guy wins, he’ll leave, and another comes in. All of them shuffle and circle around, sometimes laying bets at random to avoid pattern detection, etc. It can really hard to spot these guys.