The major flaw on martingale is the player getting greedy or relying too much on autoroll. That is when martingale become very risky to the point of devastating to someone's bank roll
Greed has ruined many a gambler indeed
However, I don't agree that autobet is the major flaw of martingale, or a flaw at all. Again, it is how you use it and for what purpose exactly. If you are going to beat the house edge through variance, autobet is a blessing as the more rolls you can make per unit of time the better. Metaphorically speaking, you are not going to catch the cat by its fat tail after 10 rolls. Fortunately, the larger the number of bets you account for (that's the crucial point), the more reliable martingale becomes
This type of talk has been around for a long time and I am pretty sick of it. What people and me trying to say here is that, if you want to make money as in "this is my job and income" type of money gambling, you can't. Because, the "play for a while, stop when you are ahead" will not happen in the long run because you can't stop while you are ahead, you need to keep playing to make an income.
This kind of case needs a lot of discipline. And it had been talked in some threads about people earning their living through gambling. I agree, most people will end up losing but there are few exceptions since they really know what they are doing.
This "you can't play against house edge and win" idea is basically not for few time tests, it is said so that nobody actually tries to get into gambling as a profession and make money. Sure go ahead and do that with poker, because that is against other humans, but it is not possible to make your living with gambling.
Gambling game creators, gambling staff, Casino owners, and some gambling players make use of gambling as source of their living. I bet you won't disagree with that. The gambling environment does not compose of players alone.
In that sense, you will need to do 100 million bets, or 1 billion bets, because in the end we are talking about full income from gambling meaning constantly gambling without ever having to stop. And if you don't stop, eventually you end up losing.
Gambling is not supposed to be a source of living for players but a kind of entertainment where they can unwind and remove stress from their everyday job. But still, there are people who tends to adopt in this kind of environment and make a living out of gambling without having a single bet on the table.