but who will consume it otherwise, when 100M people are creating 100 versions each themselves?

You answered your question yourself. A lot of things will be personalized so a lot of them will just be shared in your own circle. Like YT videos, high quality ones will be shared more and get popular. But it isn't about popularity anymore. It is about knowing what you want and being able to find/make it yourself. Similar to how you used personal photos as wall decoration in your home, people will appreciate their own creations more.