When society was organized into classes, people in the upper classes (like the father and son in the drawing to the left) learned about dress from their parents. In today's upwardly mobile meritocracy, that usually doesn't work because most men's parents don't know much about dress either. My mother, bless her, has at least a hundred pairs of shoes but never told me that steam removes wrinkles without dry cleaning (though it's definitely possible that she did while I wasn't listening).
Lacking parental guidance, most of us learned about clothes by observing our peers and seeing what was for sale in the stores. In our youngest days we were hardly aware of what we wore, donning what was given to us. That changed as soon as we got old enough to learn where the other kids clothes came from. Under intense peer pressure (young people are far more conservative than any other group), that probably became the same place we lobbied hard to get our stuff from. But, NBA logo gear can only take a man so far. For dressy occasions off the court, even the NBA elite wear suits.
After a first position is secured, the rules of dress become less relevent until a man moves into a job that requires contact with businessmen outside of his organization. Business casual is usually appropriate garb for young analysts and lawyers for a couple of years but after that the dress of executives and professionals around the world is the suit and necktie. The apprenticeship period, as it were, before a man is sent out into the world, is when he must learn to dress in wool rather than the cotton (and synthetics) that he has relied upon for so long. He has the luxury of acquiring a wardrobe before he needs to be deploying it every day. And he must.