To draw objective conclusions about further development cycles and some kind of statistics, we must wait for the release of episodes 11 and 12 and see how long it takes. It is extremely premature to call something a trend now. The development of the 9th episode really took less time, because the work on the interlude also took time. So if you combine the interlude with episode 9, then combine the number of renders and animations too to be objective. Everyone became such an experts and foretellers after episodes 9 and 10. Where they all was for the first two seasons?
The math:
Interlude: 794 renders + 36 animations
Episode 9: 5037 renders + 303 animations
Int + EP9 combined: 5831 renders + 339 animations
EP10: 5868 renders + 335 animations
EP8 release date: Nov 19, 2021
EP9 release date: Dec 16, 2022
EP10 release date: Dec, 8, 2023
What's happened between EP8 and EP9 releases on the DPCs side? He passed through a lot of troubles and personal stuff at first. At second, he had to prepare the Season 2 release on Steam, such things takes time too. What else? The whole and a new "branching" system and part of the game. Brand new mini-games (you may like them or not, it's pointless to discuss, it's HIS game), etc. But still, he had managed to make a release in 13 months.
What's happened between EP9 and EP10 releases of the DPCs side? He had to took a vacation to vent a bit after years of development. He spent a lot of time on hardware upgrades too. Almost half of EP10 was made on old equipment, so the progress was slower than it would be if he had 4090s rigs in Dec, 22. What eventually? 12 months release. Safe to say that it could be a 10-11 months one, just taking in mind his 2-weeks vacation and time he used to upgrade/add rigs.
Static renders, scenes and branching doesn't slow the process that much. The animations does. He always manages his development it in the way, that his rigs constantly have to render something - mostly animations, because static renders may be produced ALL in a few weeks, posing takes much more time, but it's still simpler than doing animations, especially in DAZ3D.
In short, we have to wait and check out how it goes with EP11-EP12 this time to make any really accurate and objective conclusions, according to new episodes size, renders and animations numbers, etc. Too much negative foretellers lately. It's hard to stay optimistic, but always easy to stick to pessimistic trends and spread it around. But you'd better to stay realistic at least.
Just cut the crap, like he is milking or prolonging it purposely to earn more money. He is already millionaire. If he hadn't been fanatically devoted to his idea, he would have abandoned this game long ago, and not continued development with so much money on hands. To have so much money and continue to invest almost all your time (years!) into development - this indicates its real goals and qualities.
He wants to bring his idea to life and do everything he has in mind and implement it in the way he want. And judging by the public interest in the game, which has not faded away for so many years, but on the contrary is only gaining momentum - he is doing everything right.