Its very simple like you say - but its difficult to explain to the addicted gamblers who only think of their wins and cant stop even after they win a big because their greed wants more - and that greed s never satisfied. It is possible to control your greed and not gamble like crazy. Then it remains a mode of entertainment by paying the casino owners - in that way.
Almost everyone wont stop when they are on winning streak. If you managed to turn $100 into $200 then probably you wont stop right there until you lose few of your profit. Some people are smart enough to stop when they suffer small lose while some will keep on going until they could keep on winning again
It is true that you can't stop when you enjoying winning and if you lost profit you will not accept it until you play continuously if you go into bustabit you will see lot of people there who actually making profit they playing smart enough to defeat the script on it they don't tolerate the short term period of playing they will play until they get what they want. If i were there once good profit is enough and then withdraw or save it for future purposes.