Google is not even close to that kind of monopoly. Every one of their products has viable alternative, and plenty of anti-Google people get by without using them.
That certainly isn't true of youtube. It, exclusively, holds a lot of videos. It's not like I can just watch random youtuber on vimeo or some kind of gnutube.
FWIW, about a third of the high-quality creators I subscribed to on YouTube initially, also maintain a presence on Nebula.
It's not enough to fully switch, but at the very least I get their stuff without mis-gendered advertising — as seen the other day on YouTube, where I was presented with an unskippable ad for sanitary pads.
None? Though looking at my subs list, the low quality channels are mostly personal friends sharing stuff that won't have a broad reach, much like my own is now I'm not making indie games.
(They also post so infrequently that I forgot I'd subscribed to them).
No idea what you mean by "that kind of monopoly". Google is a company which performs illegal acts to preserve its monopoly. Of course that will limit the viability of competitive products and services. That's why it's illega.