That’s not true at all. Fame for no reason or dumb reasons is hardly a 21st century phenomenon.
No dog in this fight, I don't know what exactly you're doing, but I'd cautiously point out that it is, in fact, novel to the internet era to watch rando microcelebrities doing makeup step by step, no matter how long we delay acknowledging that with microquibbles.
I could throw in an example of how I'll watch boring videos of a couple playing with their birds for 90 minutes on Youtube. You can link me to the Wikipedia page on slow TV (via Norway), and it won't erase the simple, boring, straightforward, fact that it is a phenomenon.
I didn’t interpret the original comment to be about micro celebrities, but about people supposedly wasting time today in ways they didn’t beforehand. I agree that micro celebrities are a new phenomenon somewhat (although they are also sort of a return to more regional distribution of fame.) But that wasn’t the point being made.
The scale isn't even close, and it's become normalized now. I think it bears talking about as a 21st century phenomenon.