The main reason people care about QMK is that it is open source, and then of course all of the benefits that come from that. It wouldn't be voiced so much if the fact of the matter is that ANY software could be open sourced. It's one thing to say X software is better than Y, but why not prove it by showing the code?
I can't tell if there's a language barrier thing happening here or not, but I'm consistently confused at the notion that the LDN series boards are not QMK-compatible because they do not want to open-source the PCB; as best I understand, there is absolutely no requirement that the PCB be open-sourced for it to run QMK. Indeed, the QMK repo contains configurations and mappings for what seems like a
significant number of PCBs that are decidedly not open-source.
The firmware itself is open-source, sure, and porting a board to QMK absolutely involves mapping lots of pinouts that could, I guess, be used to recreate a PCB in an incredibly rough way, but it's not like kicad or eagle or whatever files are in there; I don't know that what is contained in QMK would make a board any easier to reproduce than any number of widely-available photos taken and renders produced of that PCB (and certainly it would be less useful than having a board itself and inspecting it).
Anyway I have said too much already and I've already made my stance fairly clear: I spend too much time working on a mac, too much time writing custom lighting modes/options for my boards, and too much time fiddling around with my keymaps to give myself all kinds of little nice-to-haves for my development process to get a board that runs a firmware whose source I can't modify. I have no hard feelings with this team: they do great work, and I'm sure it's plenty/enough for lots and lots of the folks on this forum, but their work just doesn't support what I do and I can choose to either get over it and stop complaining about them doing their own thing or be a jerk on the internet. I'm gonna not be a jerk, let them do their own thing, and wish them the best with this and all future work.