The issue isnt "Price", i agree that $5 isnt bad, the problem is the shady business practices.
The page for lewd mod 1 promised buyers all future updates to the game. (And it was removed when lewd mod 2 released so basically a bait and switch)
The same promise was on this page aswell until it was pointed out in the comments that if the games is broken up into more installments it would be a bait and switch again.
The normal thing developers here do when their games get bigger and more content is raise the price, not break it up into several games.