It was necessary, the game was about to be finished and the creator needed to find a way to extend the game in order to further milk DRY the patreons and continue the endless development cycle. What better way than to remake it and start from scratch? The fact that there are people still supporting them is why they do this, so long as there are suckers who subscribe to this, it'll continue to happen and expect it again once the remake reaches v0.9 and a new koikatsu skin layout becomes popular. Remember that you or me, people who make smart financial decisions aren't the target audience, it's more like whale fishing for people who would buy into Kickstarter or subscribe on patreon.
Sadly that is the mediocre way out to keep milking
other developer may think to finish the original Idea so he can keep adding content
DLC + More storylines + Characters
The game may be "finished" but there's always more room to add things before jumping to another project
may be this time different from the last, or similar to stay in comfort zone and suscribers may feel satisfied as well
but no, he decided to do 2 things
Add a fuck ton of unimportant characters besides the family, one more poorly designed than the other
and remake the game
kekw
at very least is trying to improve his storytelling in the hospital prologue