How many songs do you have in your collection?
Let's just say 1.5 TB worth. Mostly 192kbps mp3s and higher, but maybe 10% or more FLAC.
One idea that keeps me up at night is a collection that expires itself. It’s probably like an LRU cache for music, reflecting a life-cycle that’s self-contained.
There’s a passage in Infinite Jest that describes the logical point that a quantity of meat exists that I will eat over the course of my life and it could be stored in a substantially large enough room.
Similarly with our music collections, if you will, there’s only so many tunes left. The excess is what is wasteful.
I don't know if I'd quite put it that way. Maybe infeasible for one application or another (I have no experience with Kodi). But it's not hard to simply have that many files on a hard drive, in a standard Artist/Album directory structure.
Assuming 5MB per .mp3, 1.5TB is about 300K songs. No problem for a standard filesystem these days.
Maybe mirror it with another 1.5TB drive for safety, and you should be good to go for a long time.