Older guys who dress poorly were once younger guys who dressed poorly.

I am 60 and I have always had a sense of style and often times it was what was in style at the time.

Style changes as you mentioned and people need to keep up, or they will be out of style.

A physically fit person in most cases is going to look better in and out of clothes. Also a tailor can make a world of difference in what you choose to wear and how it looks on you.