That's a great argument for how dominant Google is in the smartphone OS category, but that doesn't really say anything for whether the web is centralized. Even with 100% market penetration, there are people that opt to not use Google's included apps (such as Facebook and their messenger app).
But all if this is obviously beside the point that the OP made. Even if you don't want to develop a search engine or a phone app, you still have to tie your users to a central "cloud" service and web site so you can get discovered by google. That's a huge disincentive for p2p services.
[1] http://uk.businessinsider.com/heres-how-dominant-google-is-i... [2] http://www.idc.com/getdoc.jsp?containerId=prUS25450615