He started on Episode 1during the summer 2018, so it did take time.
You are comparing the much shorter lower quality episodes of season 1 to the larger higher quality episodes he releases now. More girls, more unique paths, higher quality renders, much longer sex scenes, to name a few things.
I calculated the development time of Season 1 starting from the release of Acting Lesson in December 2018. Still, it took him more time to develop EP 11. Keep always in mind that for the first episode he did have to start from scratch for user interface, minigames, characters definition, main assets and so on. He probably looked at those aspect before December but he could not work a lot at the coding before completing the previous game.
Higher quality renders: that small "higher quality" is due almost to better hardware, a 4090 is much better at ray tracing and has so many CUDAs that compared to a 2080TI he had when starting BaD. He has not improved his skills in a relevant way, his style and approach is consistent. He still poses quickly (hence the persisting problems with teeth, clothing fitting, materials, lights).
Longer sex scenes do not impact that much, he stated that he could output more than 100 static renderings with a 3090 (and now he has 4090) when the scene was unique with just minor posing variations. That's quite expected. To change characters sex position does not take that much time. He has made only 18 scenes in Ep11, they could be longer but they're much fewer than the past compared to overall episode workload.
Debugging of free roams and minigames takes more time.
Not sure about "most". I have seen plenty enjoy the free roams and mini-games. The animations don't take much time. The "cinematic" animations are a very small part of the overall animations.
There was someone that counted the percentage of lewd and non lewd animations and from what I recall non lewd have become the majority in last episode. I was not able to find it, if anyone can find the source is better.
The anal scene took 1 day to pose, 34 to animate.
But you have to decide if animations are slowing him down or not. Because you always said that he's not impacted by them, so what would be the deal of cutting lewd animations?
Then I still don't get how that anal animation of season 9 could take so much, while bigger ones won't. For example I take the data provided by the always useful
ElectronicRoberts in this post
This should be the 35 days anal scene of sage episode 9:
anim_sage_hm_fuck1_ep9.webm - total frames: 120
anim_sage_hm_fuck2_ep9.webm - total frames: 120
not anal I think: (anim_sage_hm_spank_ep9.webm - 90 frames)
So 35 days for 240 frames?
To make a comparison of non lewd from Interlude with the same hardware:
anim_bike_intro_epi.webm - 240 frames
anim_work_epi.webm - 240 frames
anim_work3_epi.webm - 900 frames
How much did it take for those? Or graphic cards get much hotter during lewd scenes?
You should realise that something doesn't add up.
I only go from what he has said and that is that manual work like writing, coding and creating art takes the longest time. Especially the main girl paths.
His wife helps him with the mini-games, it's a thing they do together.
We'll see when EP11 is published.
ElectronicRoberts in the past gave us very detailed statistics about dialogues, lines of code and so on. So we will have precise data to compare. He is not the only guy that extrapolates data from the game. I would like to hear more from them, so we'll have something factual to comment on.