You've got absolutely no idea what you're talking about.
Go and look up "Debbie Does Dallas", there's a very famous case where pornstars wore real copyrighted Dallas Cowboy Cheerleader uniforms for a "parody porno".
The Dallas Cowboys Cheerleaders didn't find it funny, and sued the porn producer.
They won with absolutely no problems whatsoever.
You cannot use another programmes IP without their permission. If you did something like "a hairstyle like Princess Leia", a metal bikini, in a desert and you called her "Layla", maybe you could get away with it (and when Brazzers etc do their "parodies" that is exactly what they do) because you're not actually using any "Star Wars" assets or IP. Once you get into the region where you're using a company's real intellectual property without their permission for a commercial gain (like 99% of "Parody" AVNs do), it is completely illegal, especially as having your IP featured pornography is considered defamatory and likely to cause damage to their brand.
Debbie Does Dallas was in the 1970s, Dr Seuss sued to stop a third party making a Dr Seuss/Startrek crossover comic, Dr Seuss won, that was 2017. The law is very solid in this department.
It is 100% illegal, you've got absolutely no idea what you're talking about. That point is like saying speeding is legal because you drive at 90mph in a 70mph zone every single day and you've never been caught and only 1 or 2 people ever get tickets? That doesn't change the legality of it.
Go and look at Dr Seuss Enterprises vs ComicMix LLC (Centred around taking the characters from, in this scenario Dr Seuss and Star Trek, and then making their own comic), it is very similar to what AVNs do, minus the porn part.
Again Court didn't have a problem siding with Dr Seuss Enterprises.
Debbie Does Dallas Case was in the 1970s, Dr Seuss Enterprises case was in 2017. The law hasn't changed.
And there's giant factories with dozens of employees out there making fake knock-off clothing, it doesn't make it legal just because there are big names doing it? Innocent Witches I learnt today has an 11 man team working on it, it is completely and utterly illegal, their art is
amazing, but it you'd struggle to find a single part of their game that doesn't violate copyright law and that's an 11 person team making $20k+ a month on Patreon. If Warner Bros and JK Rowling decided to go after them, they'd be absolutely completely and utterly fucked without a leg to stand on...
If you want to go and look up "Parody Use in IP Law" and study IP Law, you'll find there's four primary pillars to using parody as a defence. One of them is "It must mimic the original point". Not a single copyright breaching game on this site would be considered legally a "parody", wouldn't even get close to it...
Just like real porn games, any Dev using another person's IP is flying under the radar and hoping they don't get caught,
and they probably won't get caught, but that doesn't stop it being 100% illegal and they wouldn't have a leg to stand on.