Really, is gambling a fastest way to double your crypto ? It maybe not in many cases where people win in gambling but it is a fastest way to get lose of all of your money. It is not easy to say that anyone who come in gambling will be rich instantly but it is very common that people come in gambling and become more poorer than before.
If you will understand, actually it's a yes that gambling is the fastest way to double your money not just with crypto but also with fiat. But it also contains the higher risk, high risk means high reward. And every gambler is aware of that and this is the reason why some gamblers do this for sometime and just forget their reason to make money as if they are just having fun. It is not actually rare to see people become rich in gambling but they are very few.