Gambling can never become an investment. Only way is when you invest in a gambling website. So whatever the profit the owner makes, you can get a part of it. But of you meant by doing gambling, gambling and investment are not even close.
Gambling can be an investment, if you know about what are the casino's do with those people that wants to invest into their site. They are allowing people to invest to their bankroll so that it can make the amount of winning higher for the gamblers. If you want to see an example of it, you can just click my signature and visit it.
I think gambling is like investment if you have good knowledge about gambling.
Although risk is always there in both trading and gambling but we can minimize the risk in gambling if we have proper planning and strategy to play gambling, even in some format of gambling your previous experience and gambling skill. Your analysis can also help you in gambling,