but rather simply because it was ‘new’ and ‘easier’, and everybody was jumping on that bandwagon. that’s it.

No, for 15-20 years, it was pushed as the "Linux on the desktop" option. It was the primary distro people were pushing as a replacement for Windows. In fact, there wasn't a lot of options for a desktop-focused Linux. There were just a bunch of Linux distros that happened to have all of the packages for X11/KDE/GNOME. Maybe RedHat was slightly more desktop-focused, but it was still very much a server-heavy distro.

Although, I don't remember anybody claiming it was the "lightweight" option. For a time, it was the only "desktop-focused" option.

linuxmint has been going strong longer than ‘3-4 years’. a lot longer.

Maybe, but it only had a resurgence as the new de facto option from the mass exodus from all of the Windows 11 bullshit. Mint has a strange history with the desktop distro wars. Even now, there's a lot more desktop options, so you can't really call Mint the de facto one. But, I think it's one of the straightforward options for a first-time conversion from Windows.