I think the Mac displays used to be, at least at the maximum size. I vaguely recall Mac monitors being somewhat "lower-resolution" than same-size Windows monitors, just because of this. Maybe it was Mac laptops? Not sure. Certainly the original Mac 128 was fixed resolution.
"built-in display was a one-bit black-and-white, 9 in (23 cm) CRT with a resolution of 512×342 pixels, establishing the desktop publishing standard of 72 PPI"
ImageWriter prints were 144dpi, and you could verify thtat the system was WYSIWIG by holding a print in front of the screen. Also, Mac OS graphics used 1/72" pixels for years (with various hacks added soon in order to support the LaserWriter's 300 dpi)
Windows (initially?) had separate notions of device pixels and logical pixels (dialog units?) that allowed for some resolution independence. Its most obvious disadvantage was that it was not simple (neigh impossible?) to know whether two parallel lines you drew looked equally wide.
Nowadays, of course, it's a free-for-all.