It's because the gaming industry believes that its market consists of spotty, basement-dwelling teenaged boys (as well as sexually-deprived young adult males). So, they cater to their needs. Marketing.

And, according to the marketing departments, what do spotty, basement-dwelling, sexually-deprived young men need? Eye candy.

Now, I really wouldn't mind the Chainmail Bikini trope if it hadn't become such an overdone, tired cliché and if it wasn't combined with a prevalent misogyny in the gaming industry.

Now, as to the misogyny part... Maybe the developers are really spotty, sexually-deprived, frustrated men who could never get any? I can't help asking myself questions like this.

Although, every gaming industry survey that I've seen in the last decade (because they're done twice annually) says that more women over 35 are gamers than boys under 18.

They also spend more money on games.

Yet, women are rarely employed in game development, and when they are, they are paid only a fraction of a male in the same role.