Maybe there are not many devs into futas. Maybe only
Icarus Media ?
Was I already on your mind Rafster? (Honestly you admit to being a 'bear' once...)
Short answer is simply supply and demand, I don't mind either futa/trans as protag or another character in game to be honest.
That said you can find some if you're not too fussed about definitions vis a vis futa vs dickgirl:
https://f95zone.to/threads/lust-city-v0-9-premium-aid.13712/ - Decent but requires the walkthrough as unlocking the events is quite linear. There is a later version but requires translation from Russian and allegedly the dev is...well...it's said she doesn't like people translating the game. That said you play as a college Councillor in office wear so I can't complain!
https://f95zone.to/threads/translat...-eventually-enjoy-it-rj343891-kagurado.95126/ - Has a machine translation you can apply, I personally loved this one. But as with most Kagurado games the premise is similiar in each: Protag has magic dick or addictive semen or just very good at lovemaking so once you do someone once they become addicted to you.
https://f95zone.to/threads/lifeplay-v4-29-vinfamy.11321/ 3d game where you can customise a lot with your character, where you live, who you live with, marriage etc etc. My character Maria Santiago is a Hispanic futa that rose to a senior position in the office firm she works for by dicking her female boss, then her husband found out and keeps calling her to ask her to come round more often!
https://f95zone.to/threads/liliths-throne-v0-4-3-9-innoxia.3564/ Text base free roamer but you can become a futa, highly customisable too, my character is a futa human with a 21cm long, 9" girth penis who dresses in office jacket, miniskirt and heels and has addictive cum so the slaves I buy like her more.
https://f95zone.to/threads/breeders-of-the-nephelym-v0-755-3a-derelicthelmsman.2483/ - Haven't played this in a long time but last I played you could be futa.
https://f95zone.to/threads/warlock-and-boobs-v0-351-0-1-boobsgames.18692/ - Character can grow boobies so...depending on your definitions it might work.
https://f95zone.to/threads/the-company-v4-3-complete-westane.4153/ - HTML game you can play as one working in an office setting.
https://f95zone.to/threads/trixies-holiday-build-4-0-blacksheep-ovca.104055/ - Look at me recommending Blacksheep OVCA, it's cool though we get on and have no beef, when the news started I asked if he was alright and he said it was fine he'd been somehow unaffected, although I couldn't find his pornhub account anymore so...But anyway this one you play as one, it's short so far as he only recently started to get into game making.
https://f95zone.to/threads/hentai-high-school-v1-10-0-public-beta-sp1-sp4-hhs.1016/ - Really old but still worth playing, be a principal of a school (for over 18's only) and you can make them love you, use hypnosis or use chemical warfare on unsuspecting students, townsfolk and perhaps more deserving: The PTA.
https://f95zone.to/threads/futa-paradise-v0-12-kenningsly.66601/ - Haven't played in a while but it was good.
https://f95zone.to/threads/futa-fix-dick-dine-and-dash-v12282020-cyberframe-studios.69433/ - Nice short linear story with high quality 2d graphics, I like the scene in the shop.
https://f95zone.to/threads/heroine-rumble-v1-011-enlit3d.1880/ - Be female wrestler that eventually grows cock and when you face opponents you can bang them in the ring. In more ways than 1!
https://f95zone.to/threads/inner-growth-v1-3-morally-purple.43165/ I have to put this here or
Avaron1974 will beat me.
https://f95zone.to/threads/building-our-futature-v0-69-4-infidelisoft.44841/ - Be futa, bang bored repressed housewife while you work for her husbands office business.
There are others as well still in Japanese or machine translated and some won't be on this site because of content rules.
Okay now I'm bored, they're there if anyone wants some futa/trans protag games.
I think that honestly outside of the fandom and our own little corner of the internet we're not really a 'mainstream' fetish. As with that other thread shared we can also at times be divisive, you have people outside the fandom denouncing it as 'gay shit' and then inside it we argue and debate about whether it counts if she has balls or a fanny. Then you get the out there theories like it's a psy-op to turn everyone gay or the guys that start going into a discussion of transexuals, when all we really want to do is enjoy a (hopefully) wonderfully crafted artistic story. But really who'd want to step into all that? Especially new devs?
Not to mention having it not as a main but as an option requires much more work, each scene has to be re-done to account for the futa character, so if a game has 120 sex scenes in a male playthrough, then adds a female one and then adds a futa that's a total of 360 that has to be done, and I suspect anyone looking at that number will turn that many degrees and walk away.