The bit about replacing folder hierarchies with tags and search reminds me of some ideas that are actually pretty old now. Back in the '80s and '90s, there was a wave of interest in replacing the traditional filesystem with a relational database, for most of the same reasons as outlined here (we can store more files than we can meaningfully organize, hierarchical organization doesn't really fit lots of use cases, searching is easier than clicking up and down a hierarchy, etc.).
None of these ever really took off, though. Mostly this was because they ran into unsolvable performance problems. Hardware has come a long way since the mid-'90s, though, so it'd be interesting to see if those ideas that were impractical then are practical today.
This led to a bunch of different products and almost-products, like Apple's "Soups" for the Newton (see https://en.wikipedia.org/wiki/Soup_(Apple)) and Microsoft's WinFS (see https://en.wikipedia.org/wiki/WinFS), and the original file system for BeOS (see https://arstechnica.com/gadgets/2008/03/past-present-future-...).
None of these ever really took off, though. Mostly this was because they ran into unsolvable performance problems. Hardware has come a long way since the mid-'90s, though, so it'd be interesting to see if those ideas that were impractical then are practical today.