I used Instagram as an example because I think Facebook has done a lot more with it than, say, Google has with their YouTube acquisition. YT has been largely stagnant in the face of competition from Twitch, Netflix, Spotify, etc. and I see fewer and fewer content creators using it, whereas Instagram continues to grow.
You could argue that youtube's rate of innovation is low. But when it was launched it was Flash-based sub-10-minute low-resolution prerecorded videos that paid creators nothing, and so on.
Now it supports long videos, 4k, streaming, html5¹, pays content creators enough there are a bunch of them doing it full time², has an ad-free premium option, it isn't at war with music labels, and it hasn't been bankrupted by bandwidth costs.
Seems a fairly good track record to me.
¹ Arguably Youtube was one of the big forces getting decently working video out of flash and into browsers. Along with Apple refusing to ship Flash on iOS, that is!
² Admittedly at the whim of fickle algorithms, so not the best financial security there
