I see a lot of complaints about this on the site but not every dev who takes a while is milking it. The standard for porn games, especially visual novels, has increased dramatically. Visuals, story, writing, audio, animation, you name it. Games take longer because, if you want an audience, you have to put in a lot more legwork. That, or cater to an extremely niche audience who will pay diligently even if there's not a whole lot of them. And remember, most AVN devs work solo.
That's not to say there aren't milkers out there. There absolutely are. But length of development time isn't the best way to sniff them out. It's the contrast between time taken, content produced, details provided and consistency of milestones. Caribdis has been able to put out extremely high quality work in every update, rarely ever had major delays, and been pretty up front about progress when making community announcements. I think if anyone's earned grace, it's him.