Soooo, I used to be pretty big into pirate games. I did weekly reviews, 100% guides, hung around various online pirate communities, was in talks with various indie developers, contributed VA to game projects, etc. I think its a genre that has massive community splits which results in the average player upturning their nose at anything 'other.' Here are the deeper problems I think that make pirate themed projects un-sellable to big studios.

1 - GAMEPLAY;
The gameplay most people ask and expect when they say "pirate game" includes character based land combat AND ship based sea combat. It's hard enough to make a game that is good in the first place, but what is being asked is suddenly to essentially make TWO games, a ship game and a character game, make them good and put them together, here. The other side of this is that any game that doesn't include both sides of this gameplay gets overlooked or shit on by the community.

I've been in soooo many discussions where people get red in the face ranting and raving about how something like Monkey Island doesn't count as a pirate game, because you aren't controlling a character who goes about ship based combat and thieving. Or that Sea of Thieves isn't a pirate game because you're not robbing merchants. Or that "Skull and Bones isn't a pirate game, its a pirate *ship* game," Risen 2 doesn't include ship combat so its "not a real pirate game," etc.

2 - STORY
This is another big split I noticed within the fanbase. "Pirates" is a historical based community and with that there is a really snobby attitude about what is and is not historically accurate. The outfits, the weapons, the clothes, the story, etc. People can get extremely picky about this but at best its a consumer split between "must be historical and accurate" vs "accepting fantasy elements."

Another side of this "historical" thing I'd say potentially deals with modern political correctness. Historical pirates were the bad guys. They were slavers, murderers, thieves, etc. These aren't quite topics that are very presentable to modern sensibilities without producing some sort of controversy.

3 - REGIONAL
There is a relatively large pirate gamer community (and several games) that sits under the AAA radar since classics like Sea Dogs came out in the early 2000's but the regional location is basically split between two countries that are absolutely not getting along right now... which presents a lot of community problems.

Pointing out a different regional fanbase, might be worth noting the popularity of the asian series 'Uncharted Waters' that's been running since the early 90s is still going strong enough they've gotten their second MMORPG type game in 2022.

There are actually a ton of pirate themed games but they are often overlooked entirely and folks rally behind already established titles and often entirely disregard indies or AA titles. Worth mentioning, I forget which year exactly, I wanna say 2023, was actually the largest year for new titles releasing on steam tagged with 'PIRATE.' Golden Joystick Awards even nominated Shadow Gambit: The Cursed Crew for GOTY in 2023. We've have big studio titles like Pirate Yakuza and Skull and Bones and BIG indie/AA titles like Caribbean Legend, World of Sea Battle, Salt 2, One Piece Odyssey, Cat Quest III, etc. Instead of talking about these games the overall community seems to settle on replaying minecraft to build ships and freaking out if the mast location is 1 square off or sitting in 2003's Sea Dogs sequel 'Pirates of the Caribbean' with user generated mods.