As a bloke I think I can see one reason why - I buy sports kit the model looks good in but I won’t. Every damn time! Then end up buying again.
People buy heavy SUV when compact car would do, "dress for the job you want", "temporarily embarrassed millionaires", nationalistic fervor for your country getting more territory when even with the current one you don't know what to do, and so forth... Humans are an aspirational animal, and it is pretty easy to sell into that aspiration be it a ticket to Moon or a nice looking on the model jacket :)
To the commenter below:
Exactly. The societies where aspirations have been dampened or completely suppressed have been collectivistic and/or totalitaristic - USSR, North Korea, etc. - ie. where individual will is totally suppressed.
Then just try it out and if does not look good don’t buy it.
I believe that’s how most of us try clothes out. It’s not only a matter of body shape, but also skin color, hair color, facial hair, face shape, hair cut…
You always need to try out the clothes before buying…