In a CRT your resolution is defined both by the frequency response of the electronics and by the pitch of the shadow mask. Further complicating things is that the shadow mask has a pitch but not a definite position. The electronics don't know which specific hole in the shadow mask the beam is passing through. It's all analog and driven by clocks and PLLs.

LCDs are very digital in nature. My display here has exactly 2880 "cells"(not sure exactly what we call them) for each of the RGB colors in one horizontal line. For a cell to emit light it has to have current run through it. That makes every cell on my LCD individually addressable. The interface between the computer graphics card and the LCD driver logic is completely digital—each group of 3 cells (RGB) is individually specified. If you're running the graphics driver in this "native resolution" then 1 pixel on the screen corresponds directly to these 3 little LCD cells.

Now, some LCD screens aren't like that—some have weirder pixel layouts[1], but they are still individually addressed, unlike the phosphors (or shadow mask holes, I guess) on a CRT.

[1] https://en.wikipedia.org/wiki/PenTile