Earlier quoted context omitted.
It’s funny if the poster is actually complaining about grain. Digital compression, like the one that Netflix uses, will often clean up the image of grain as a secondary effect of the compression algo. Essentially grain is a lot of detail that video compression algorithms have been taught to ignore/remove. H.264 was notorious for virtually removing all grain making it impossible to have authentic film grain on YouTube…
I wonder: If film grain never existed, would we invent it? If we had originally developed film technology where everything looked completely clean, would anyone have thought "Hey I've got a great idea, let's figure out how to make this look grainy"?
Yes, but it wouldn't be used across an entire film. Likely just in flashbacks and other dramatic scenes, the way it's applied to digital productions today.
Similar to how in the 2000's, hipster bands added photographic pops and crackle to their tracks as an artistic measure.