It also doesn't matter whether it's true if the majority or not- "Instant transitions are only good in theory" is not a true statement. Instant transitions are good in practice for many people and that has been true for decades.
Maybe software programs got faster with our faster CPUs but all the animations just made everything feel slow.
Your experiences are not universal.
Probably because I had run into some apps with bugs when animations are disabled, and making them run twice as fast as normal is more compatible and reduce the annoyance enough that I forget its enabled. Apps that animate at normal speed in defiance of my settings get deleted.
But I also set windows not to show window content while moving or resizing, because I find that to be annoying too.
Reducing duration or eliminating animation is one of the first settings I do on a new install.