I both agree and disagree. For sure bankroll management is crucial to have any chance of long term success. A bit like you cant be a safe driver without maintaining your car. But maintaining your car is not enough in itself to make you a safe driver. If you drive intoxicated at 2 times the speed limit, it will still be unsafe even in a perfectly maintained car. And in the same fashion bankroll management in itself will not make you a winning poker player. If you are using really bad strategies, "bankroll management" will only determine, how long it takes to lose your money
That comparison is flawed, though. Variables applied unequally.
My core statement was "bankroll management is the main thing that separates winners from losers".
It was not "bankroll management is the main thing that separates losers from even bigger losers".
In other words, bankroll management separates winners from losers to a much greater extent than playing style does.
In the way I meant it, that statement assumes a basic knowledge of game mechanics, hand rankings, etc.,
But it actually doesn't have to...
Last year, I successfully live-tested a bankroll strategy based entirely on shoving blind at the first opportunity, on every hand.
The only variables I allowed myself were related to game selection and playing time, with playing time almost always being a single-digit number of hands. I would certainly argue that blind shoving at every opportunity would normally qualify as a "bad strategy". It was only a 5-week sample (perhaps 120 games played), but the experiment finished in the green, and was only in the red for 9 days out of the 5 weeks.
Obviously that's not a sample size you'd want to risk your life on, but given the extreme parameters of the playing style I imposed on myself, I think it's more than enough for proof of concept. I used this experiment to demonstrate the importance of bankroll management to the players I stake - especially those with good poker instincts, but who also have terrible self-management skills.
This was done too recently to show an impact yet, and it was combined with other lessons/examples, but I've had a few players tell me that the extreme nature of the playing style I used helped them cut their losing days down, with one guy saying it "lit a fire under him" because he was embarrassed to realize "a blind-shoving monkey has a better ROI than me".
Food for thought...
change instances of free poker into a link to https://www.cardschat.com/strategy/free-online-poker-game/