Even with high bankroll martingale can easily eat and deplete you fund especially when you encounter a series of reds in your roll. 20+ red streak can possibly make your bankroll negative and we all know that 20+ read streak is very possible. I even experience this in spinning a slot. 20+ dead spin. Imagine if I martingale my bet and I experience that 20+ streak.
If someone doesn't realize that getting to 10+ is a sign, he should stop immediately and doesn't stop gambling. Instead, he will only run out of money if he uses big bets, especially if he gets 20+ a series of reds.
For slot games, usually after getting several losses, we can get a win which, even though it's a small win, can make us continue to gamble. So for gambling, I think it's really worth it if we stick with small bets even though we have a big bankroll because it sure hurts to see all our balances used up that day.