"You are not taking a chance at all -- if you always overbet your bankroll (as determine by the Kelly criterion) by more than 2x, then you are 100% certain to go broke.
There is no chance at all here..."
On the contrary, nothing is 100% certain in the game. People have started out underfunded and with good breaks and disciplined play had a lot of success, and others have started out with a proper bankroll and seen ruin. This is a positive expectation game for us and with any luck at all our bankroll will increase to proper Kelly for whatever stake we are comfortable playing, just as easily as a negative expectation player's bankroll evaporates before he walks away from the table. I started out playing $15 tables with $500 in my pocket this October and now I'm playing $25 with $3000 (High-Low, 6D, LSR, S17, DAS). Lucky, yes. But let's say I lose my $500 bankroll, I just have to wait until Friday to get another one. So you could say that as long as you have a job with steady disposable income you have an unlimited bankroll, and if you don't have such a job you might want to consider steering clear of all gaming.
Every one of us here has seen a bad player turn $500 into $3000 in a couple of shoes, no reason a good player can't do it taking months.