Given Facebook is like 10% of total Internet bandwidth, I'm curious what happens when all that traffic suddenly gets "redirected" elsewhere by people going to o

Given Facebook is like 10% of total Internet bandwidth, I'm curious what happens when all that traffic suddenly gets "redirected" elsewhere by people going to other sites and platforms. Could YouTube cope with a sudden 10% uptick in streams for example? Edit: YouTube seems now to be defaulting to a lower bitrate, leading me to guess it's a demand issue.