So unlike what tons of people are saying, you're not actually wrong here - the game currently is built in a way that requires each scene/costume combination to have its own fully drawn image. That means that if Lex has 3 costumes and Miss Martian has 5, that means that they'll draw 15 full versions of each sex scene. This means that each new interaction and costume requires increasing amounts of work.
That being said, the game didn't have to be written this way. They could have figured out different ways to use and reuse assets to make creating new scenes a streamlined process while also cutting down on disk space requirements. However, the team probably didn't identify this as a problem right away - and now, they'd have to rework a truly massive number of content to get it to work. The worst part is that the longer they continue without doing a rehaul, the more work it's going to take. The general term for this is 'tech debt'.
The patreon model is actually hurting them here - they're constantly in a rush to push out more and more content, so they can't justify taking the time to concentrate on backend without visible results. It's not a trivial problem. I think that the team deserves some pretty hefty criticism for getting into this position, but you have to acknoledge that now that we're here, it's not something that can be fixed overnight.
If I were in charge of the team, I'd dedicate some time to figuring out a more sustainable approach to art and start implementing it immediately. I'd make sure all new art uses the scalable system, and slowly rework the backlog of old content over the next year or so while continuing to put out new stuff at a slightly slower rate. (They could be doing this already, idk)