The problem you have “need to make symbols/footprints myself, even if publicly available” won’t be solved by “lumping symbols/footprints/3d models together in one big database”..
So far I did make all the symbols and footprints I use myself.. and 3d models I only reused the resistors.
I don’t trust the stuff that’s available.
And the only thing that would make my life a bit easier would be a better footprint editor and some more consistency in workflow for eeschama/symbol editor and pcbnew/footprint editor.
They’re already working on getting rid of cvpcb and having a more direct link between symbols/footprints as this makes more sense for most people. You then chose the package within the symbol editor and it is linked there, not later with cvpcb.
Conclusio: I like to keep the basic pieces separate - if there must be stronger links the way of approach taken now is OK (linking of footprints in symbol editor).
PS: if anyone sees some 3d model he likes in the pic, just contact me, I’m happy to share.