The bankroll is not so simple to conceptualize in that simple idea, that is why I always mention that the phrase "only use money that you are willing to lose" is ridiculous, that phrase works for recreational players, but not for those who manage a bankroll.

If a player, as you wrongly mention, "runs out of money" he will stop playing, if you are a recreational player yes, but for a correct bankroll management you do not stop betting because you had a bad day or a good one.

It is actually quite complicated to explain something that is the soul of professional players or candidates to be one.

Another thing is to think that this concept only applies to sports betting, and in reality even casinos handle by law a Bankroll to operate, that is, when a Casino runs out of Bankroll  does not say; "we do not pay today, come tomorrow"... that example is worth recreating in the subject in question, the Bankroll is lost and we go bankrupt... it is starting over.

Many or most players make the mistake of starting to look for profits, when what they have to do is start managing their Bankroll, making it solid, it is a long, very long road to getting a solid Bankroll, in short, all over the internet and even in this very forum, you can find the famous phrase: "use money that you are willing to lose or money that you can afford to lose", shit no, it is the opposite: use money that you do not want to lose, fM said it.