Not always true. I just recently watched video about Tandy VGM-225. Which had bad picture. Most likely due to being reused cheap TV. You can't magic more resolution out when you do not have enough "subpixels"... That is the grid of holes is too coarse compared to resolution.

Then again this is early 90s CRT most likely with design from 80s just upgraded to display VGA. Later and more expensive CRTs got much better.