Again: #61209 - Always write unused IDs on save - blender - Blender Projects
Discussion with devs is ongoing in there. Most of the things discussed in this thread are even already on the bulletpoint list. Including “make save default and add toggle to potions”.
It’s been open for four years, though. Maaaaybe, since Blender now does breaking stuff on major new releases, version 4.0 would be a good opportunity to work it over again.
(also again for sake of thoroughness: Proposal: Explicit Management of Data Blocks and (possible) Deprecation of Fake User)
(edit) BTW - 1D_Inc’s requirements and own observations about Datamanagement are mostly in the design task, I just noticed. Lower third at the moment.
(edit2) and everybody who hasn’t yet read the Link with the design issue yet - do it. Even though I am still opposed to Blender quietly deleting actions and materials by default there is quite a lot of really important observations in there from both sides of the argument. And I think I will have to first think about all of this a little more before I further comment on this thread. 
Yes. I read all of it
No. Still not convinced it has to be a binary choice of all out data-loss or all-out data bloat.