Why is this topic being bumped every year

That's true

The main Nspire support piece missing from libticalcs is nested folders support. It's an infrequent feature request, which testifies to both the mild number of TILP users (even if it's certainly on the rise, due to the rise of Linux usage and the fact that it's been possible to use it on Windows alongside official software for more than a year and a half), and the infrequent usage of nested folders. People usually use a single level of folders on their Nspires, like TI-68k users do.

A while ago, I had started making the necessary changes, in fact
When I stopped, the enumeration part in libticalcs was alright, but the layer above that (translating data structures for building the UI) in TILP wasn't. Then, I moved on to other areas of development in the libti*/gfm/tilp code base...

In my TODO list, I don't remember whether I tentatively put the entry in the TILP II 1.18 development cycle, or whether I set it aside for later. However, since there is an actual user for the feature, it might move up, if I find the time.