Let me break down your point.
1: Even free art can have criticism/suggestions its part of the art world.
2: As for art. Hiring an artist saves you time (if it takes you 20-30 per) by a lot. As for "I can't test until I have the image" use bad temp, it should be easy since... it's a 2D game. A little doodle to test the code. As for why simple AI (unedited) as the same glossy look and is loaded with hard-to-spot errors most of the time (depends on the program but you get it).
3: Yeah.... the program you showed is simple. I get learning programming can be hard for some folks, but... anyone who programs can agree a VN is one of the easiest game types to program (since all the code a VN uses is very simple.)
4: Writting a game is hard, I never said it wasn't.
5: Yes.... I know nothing is "free" truly but.... (IDK how you didn't figure this out) I was referring to money.
6: No, they don't, if you want an example (since you're an MG) fan look at Mr.Nickname's work. He makes a bunch of VN with no ai. Other than code
7: Finally (since I hate this point) "Why is that "better" than generating images yourself that you have immediately? " ahem.... Its objectively better in every way for one any game, comic, of anything using AI images due to the current law you can't copyright it and (its iffy) the big Disney is currently suing some gen AI companies. It might be fine duh but new laws could be made making all gen AIs useless (since if they can't use mostly stolen artwork.... gen AI will learn much much slower/get dumber once it forgets all of said images). If your just making a fun quicki game yeah its fine but its risky if you want to do something long term.
Anywho thats all if you guys wanna make a war out of this go at it I'm gone lol.