On a personal level, I agree with you. I play everything.
But the internal data for more diverse lineup for Overwatch and other shooters with heroes probably shows encouraging numbers in terms of representation and how it relates to dollar spent. In fact things like Apex, Valorant, Overwatch is probably the genre where they'd benefit the most with varied characters that all have different skins for MTX.
Probably the most absolutely bonkers data point I've ever seen in terms of representation and player usage would be this particular
reddit discussion that includes Rea3(League of Legends Lead Gameplay Producer).
In there he talks about gender balance in champions:
Overall that seems entirely logical, they are way more male champions than female chamions, so making an effort to get this more 50/50 over time is probably a good idea.
But then some angry gamer™ had this to say:
His reply to that angry comment is where things gets REALLY wild:
Of course this is only a singular game and is not reflective if the entirety of the gaming space. But the fact that LoL female players literally will almost NEVER play male champions and thus never buy male champion skins means that in reality, it's probably better for the ratio of female to male champion in that particular game to be more even more than 50/50.
They'd make more money because each champion would be played by more than male players.
Anecdoctally, female LoL players I interact with reflects this reality, they all play cutesy mages mid lane, or play female AD Carry/Support in the bot lane but I did not know it was that lopsided in terms of play pattern.
This whole thing would probably also explain why in LOL, the champions with the most abyssal playrate are often male and/or a monster champion(which is the furthest away from beautiful female champions).
TL;DR If companies keep making more diverse characters(sexuality,ethnicity, etc..) it's probably because they see monetary returns on it, because that's the only thing these big corps do think about.