Because at least for Linux, its desktop support is still severely lacking. Maybe it's the distribution I was using (Ubuntu), but all i wanted to do was hook my laptop up to my monitors and use the external monitors alongside my laptop monitor, like I do on Mac or Windows laptops.
I failed.
I remember hand coding an XFree86Config file almost two decades ago to get three monitors setup.
So yeah, that's why I don't work with Linux on the desktop. Because it doesn't work for me on the desktop.