Also 80x25 has a lot of history, and some things work better at that size.
I don't know if you've ever tried using a non-graphical display on linux recently, but if you have say a 4k display, you get unreadably tiny text. It also breaks a lot of text-mode stuff.
If you've ever tried to FIX this on your system, you'll find a bunch of roadblocks.
You can't just use an easily available font for the console. Console fonts have to be created or converted into a non-standard .pfs or .pfsu format.
most linux distributions have at most a 16x32 font available if you take the time to do the override properly. Even that font is pretty small on 4k.
When terminals were common, they pretty much all were 80 or 40 columns and 25 rows, not a lot of choice, most were about the same size.
I actually like modern emulated terminals, with all the bells and whistles.