My guess is that Illusion either allowed or ignored people using their game Honey Select's assets to make scenes for visual novels, although apparently AVNs made using it can't be sold on Steam, so probably "ignored" is more accurate.
Unless someone else buys the rights to HS and starts cracking down, the only thing it would mean is that the original program would no longer have any official support tech-wise, although it also sounds like there's tons of mods out there, so the modders might keep supporting it. New devs would have to either buy the program in the next 3 weeks or grab it from somewhere like, well, here, to use it in the future.
The real issue would be if someone does buy the rights and starts cracking down on people using it to make their visuals, like this game, My New Family, Ripples, etc. It would probably prevent them from monetizing their games on the currently-available sites ... maybe they could continue by removing all evidence of the actual games from those places, but it would make it hard to find any new players without directing them to the Patreon/Subscribestar/etc. from, again, places like here.