I agree.
Because no one aspect of trading will, in itself, give you an edge.
Edges come only with patience, discipline, statistics, probability, education, experience and practice (there are no productive short-cuts).
A lot of beginners start off imagining that all they need to do, to gain an edge, is to copy something that "just works", typically without appreciating that doing that successfully necessarily entails first learning to distinguish accurately between what works and what doesn't. And doing that is no trivial matter at all, partly because (for various reasons - some very obvious but others far from it) the internet, in particular, is full of misinformation about trading. In a field of endeavour from which so very few people ever manage to make a living, it stands to reason, in my view, that the overwhelming majority of the "information" with which one's presented is actually quite likely to be seriously misguided. Which is, of course, one of the many reasons why overall success-rates are so very poor.