Most of these 'versions' are just different packaging or something though, they don't usually change the game. Companies just don't see the point in releasing an all-ages version. It would be great if some of them would try it, sure, but these companies aren't big enough to be taking risks like that. Also even if they do release an all-ages version, it will still be connected to the 18+ version, so it will probably still put people looking for non-adult games off buying it when they google it and see a load of H-scenes.
As Steve mentioned, these games are made for a Japanese market, where this kind of sex sells. If you want less H content then your best bet is to focus on the Western VN developers and support them, and try and get more all-ages stuff made that way.