Hmm, thanks. It's been some time since I last played that, so I had to refresh myself on the specifics by picking it up again for a while.
It's somewhat different from what I was expecting for that model, since the short story arc that they consider the main quest is almost inconsequential. It barely matters that the main quest
exists, let alone that it's completed.
The bulk of the game is the sidequest routes, so in essence the ongoing paid development is the "main development loop" rather than "post game-end life-support".
Compare that to something like (the proposed plan for) Lilith's Throne, where you'd get a full RPG-with-porn main quest that would dwarf any individual sidequest chain at least fifty times over.
If we actually got the complete main quest, we'd be able to have a full and satisfying gameplay experience from start to finish, with no loose threads.
That's why I was curious whether any game had managed to utilize this model beyond its endgame; it seems difficult to continue to attract sated players with the promise of ongoing content that would never top the already-completed main quest in scope or scale (and bearing in mind that this is a porn game, the events leading up to and including Lilith's defeat should also contain a ton of quality smut unless corners are being cut).