The rules in poker are much more well-defined and it's easier to acquire information from other players, books, training sites. The main difficulty is probably the work you put in and the amount of hands you play. It's also a relatively fair game (UB/FTP scandals aside).
IMHO trading is a very different beast. Institutions have advantages which you won't begin to comprehend until you've actually traded for a while and your bankroll gets cut in half. In a sideways market, trading is a zero-sum game and if you take a look at the obscene profits the bank traders are making, you can infer how well the typical retail traders are doing. The banks basically get to lie, cheat and steal at your expense.
There's next to ZERO sharing of truly valuable information even on trading sites like this. There's a ton of information on bankroll management, psychology, brokers to use, software to use. Yes, a lot of info that are requisite to being a successful trader, but you will not even get a whiff of a secret sauce. Information like that would never be shared and there are very few retail traders who are actually able to trade for a living. Most posters on this board are wannabees.
That being said, it is possible, but going back to your post, it's a very different game than poker so I wouldn't think you could leverage much of your poker skill to trading.