Because as a developer I like to try things that can improve the player experience, and I do what is necessary for that.Ask why update renpy in progin process? Can be you need to rewrite all... So why? And other i really like game but i sit out normal 3-5 updates and play with last save. WHen save is not compatile to older ähh ask your self did you like play 4-10 times again? This is why i dont like renpy update in progress. Hope you understand my point of view.
In theory, updating and improving the code seemed to solve some problems that the game presented, but it also brought some unforeseen issues too. And the most important thing is that version 0.8.2 had performance problems on some computers and had to be rolled back.
Then, I made posts on Patreon warning about the saves compatibility problem, I even made all the pertinent changes before going public, so it wouldn't hace that problems.
But still the update was leaked and people who prefer to download the game this way, instead of using the official platforms to download the update (besides not reading the warnings about the problem in the official sources), now have a corrupted save.
Even so there is a save on the discord server and on the Patreon page to use, but nobody reads anything even though I have repeated over and over again the same thing...