There is no way you will fail 7 times and if you do just increase the bet and you will get it back eventually even if you wait 12 times.
It's possible to lose many more bets consecutively.
To be successful, you need an unlimited balance which is impossible.
In reality you don't need infinite balance because there's really no way to lose 30+ bets in a row because your chances of a loss also get exponentially lower with each lost bet. I've seen people with 15 losses in a row but getting 30 is already almost impossible. Of course to be able to bet 30 times you either need a very low starting bet or a lot of money and with some of the last bets like 25+ you're going to be putting thousands of dollars at stake just to go back to 0 and be able to reset the game which is pretty bad.