It’s pretty much arbitrary what we as an industry have decided “text” means (and this has changed over the years), and what features it ought to support. It’s

It’s pretty much arbitrary what we as an industry have decided “text” means (and this has changed over the years), and what features it ought to support. It’s largely “what our technology easily supports today”. For example, most people expect antialiasing (i.e., subsampling across space) but we seem to have written off the idea of motion blur (i.e., subsampling across time), except in some games. It’s be technically more accurate to draw a quickly-dragged mouse cursor with a (correctly computed) blur, but that’s not generally easy to render today. And motion blur of moving subpixel antialiased text sounds like a nightmare right now, but with the right abstractions it might not be.