Three reasons why:

  1. Good fitness takes months or years to build; with fashion, you literally change your clothes every day.
  2. High fashion costs, but gets you into certain rooms. Still you can be fashionable with low cost, if you are artistic about it.
  3. Fashion doesn’t change the fitness (your body stays the same); it just advertises fitness body to different audiences, and makes it enticing.

Similarly:

  1. A good product takes months or years to build; with marketing, you change your ads every day.
  2. High marketing costs, but gets you certain clients. Still, you can be a good marketer with low cost, if you are artistic about it.
  3. Marketing doesn’t change your product (your value stays the same); it just advertises your product to different audiences, and makes it enticing.