There is a word for when movements become basically fashion trends or goods/services to be sold.

“commodification”

Is it cool to wear a Che Guevara tshirt?

A tshirt with RBG?

What about wearing a keffiyeh?

Commodification is the process of transforming inalienable, free, or gifted things (objects, services, ideas, nature, personal information, people, or animals) into commodities, or objects for sale.[1][2][3][4][5] It has a connotation of losing an inherent quality or social relationship when something is integrated by a capitalist marketplace.[5][6] Concepts that have been argued as being commodified include broad items such as the body,[7] intimacy,[8] public goods,[9] animals[10] and holidays.[11]

This is also something that happens often with alternative sub culture.

Goth and punk clothing is sold at high end fashion stores and the original sub culture and ideas that these groups promoted has largely been lost. (Punk to emo pipeline)

Though legit old school punk artist still push their ideas often and haven’t “sold out” for commercial success.

They keep it real. But corps still try to capitalize on their appeal and degrade it’s message by making it a trend.