I guess it boils down to whether or not they are trading their own hard earned capital. Sure give someone a comprehensive trading plan with entry/exit signals, position sizing, and everything else, and away they go. Drawndowns on somebody elses money (be it virtual money or the company's money) is no problem at all.
Most trading systems out there are percieved as crap because they are pitched to the wrong type of trader, some have high drawdowns, some require fast entry/exists, high frequency of trades, some are only tradeable once a week, stuff like that. If its not the right system for you, then you won't trade it the way its designed too, or if the drawndown risk is too great, you will bail.
I think most people look at trading differently to other professions because it is possible to "get lucky" and win at least in the short term due to the 50/50 nature of what you are doing. Not so if your performing open heart surgery or trying to build a bridge. Fact is, most people don't regard it as a profession at all, but rather a hobby that they can "get good at" over the weekend or in a few weeks. Trading tests every emotion/skill we have, not so if your a dentist and you're pulling a tooth or an electrician fixing some wiring. For them the job is straight forward and without emotion. They're job is purely technical in nature.
Was it Van Tharp who re-evaluated that trading was 100% psychology? That's probably true. The system and/or "edge" is more or less trivial in nature. Profitability only comes when you employ risk, and risk is psychology.