Sorry to sound so argumentative, but I'd say exactly the opposite, myself: in my experience, almost nobody ever becomes very capable after only 6 months. Even people who join the graduate entry trainee trader schemes of financial institutions and get highly focused, full-time, professional education take a lot longer than that, before becoming "very capable".
Another perspective strongly opposed to my own, there. In my opinion, far from being "the only way", I think very commonly experienced results actually demonstrate that that's a really bad way: in my experience, the people who do best, and benefit most from their initial live trading experiences, are usually those who've mastered the theory first, rather than trying to learn by practical experience. The skills we need, to trade successfully, are counter-intuitive ones, and trying to learn them by practical experience, without starting from a sound initial theoretical understanding, is a real mistake for most people, in my opinion. And one that's very often difficult to recover from.