Many would say that blackjack is not a all or nothing or even gambling. Seen plenty of maths gurus who are able to make a good living from blackjack using the same structures as trading (Money management, favorable setups and maths behind the game) Roulette on the other hand.... You are spot on about the variables with trading, for those that don't understand this, it is nothing more then gambling.
FYI. I was somewhat harsh in my reply's to a poster (Voly) that seemed to be going out of his way to troll this thread. It appears his posts have been deleted.
Actually there are many more stock traders than futures or forex traders. But the attraction to futures and forex trading is just one thing: leverage. You can make or lose a fortune quickly if using full margin in futures.
I think stocks are meant to be used for long term trading. And if you want to become a successful Currency trader, you must adopt short term strategies. Future can used in both types of trading. Remember to accomplish background study before proceeding.