… The developers don’t want to.
Really? Where do they say so? I must have missed that. :?
Have you spoken to them? They don’t say it in so many words.
Anyway, some of the reluctance is breaking save game compatibility and moving on the new version. I’ve submitted a new PR which fixes some of the issues which can be fixed while keeping compatibility. Not the submerge bugs, mostly.
There’s plenty of reason not to break save game compatibility. A lot of the old version functionality was broken in 1.9 for reasons I can’t fathom.