That's because that talent isn't allowed to own anything. Imagine you know what to do and how to do it. You go to YC, present your idea and ask for some funding. And imagine they'd tell you that "Yea, we can pay you this fixed salary and see if your idea works. No, we get 100% rights. No, we won't share profits, but we'll up your salary if things go well. No, we can't tell you by how much." Who in their right mind agree on these terms? That's why employees don't share any really interesting ideas: they go to YC, get money and retain 93%. Google has the right people, but it's not really interested in any changes because ads work really well. Afaik, they even cancelled the 20% time.