that's true , but there is no rejection in trading since you have no audiences or boss who reject or approve your efforts...
in trading there are no audience, no applause, nothing...
audience or boss can be fooled, therefore in many occupations (including acting) absence of talent is ok, since you can be a mediocrity and still win the hearts of public or superiors
not so in trading: no rejections here and no approvals, but also nobody to fool...except yourself
that's why you can not be a mediocrity here, it's just not enough