Just about everyone says shit went wild after the bowling alley event, and that's certainly true. Willabelle was introduced, Ryker attacks MC, Wendy shows up, I want to say Millie also arrived, which lead to fast-tracking MC knocking up Jamie, and it goes on and on from there.
I think once the game took off and got real popular, with tons of money coming in, he thought he could afford to take more time to refine the story, polish the visuals, beef up the harem (pun intended)—use his momentum to bring the game to a higher level. I'd wager the story about MC's mysterious background also ballooned out of proportion, which would require rewriting the first Season 1 to match. Probably thought "oh while I'm at it, why don't I remake the first episodes too, bring them up to scratch?"
It's similar to DPC's dev time increasing with every update—he improves his skills and equipment as time goes on, so he builds on the game more and more. Except DPC actually has something to show for all the time he takes.