Pretty sure Mozilla has the numbers on how many installations each OS has, so it’s probably a legitimate decision. HOWEVER, if they want to maintain their position on Linux, I highly recommend changing the default behavior of Ctrl+Shift+C to match how it works in Helium, where it simply copies the selected content instead of opening Developer Mode, which cannot be closed again using the same keystroke.

I doubt they’ll change that, since Ctrl+Shift+C also opens the dev console on chromium based browsers on Windows (just tried it with Chrome and Edge). Not sure if that’s the behavior on Linux, since I only use Firefox there.

Also, I really doubt that Ctrl+Shift+C behavior is going to factor into people’s decision anyway. That’s a very niche problem to have.

Can confirm ctrl-shift-c opens dev console

I keep mixing up the shortcuts because ctrl-shift-c is copy in the KDE terminal

This behavior isn’t unique to KDE’s Konsole; many others share it. Since Ctrl + C performs an entirely different function in most Linux terminals/shells, Firefox’s default behavior feels out of place. It’s admittedly a niche problem, but to me, it looks like an ‘alien’ in the Linux world.
Also incentivizes people to not use it.