Sure you could make some money, but nowhere near the monopoly profits everyone is seeking. A decentralized Google would never be as profitable as a centralized one, so where would a capitalist prefer putting their money?
IMO this is also why decentralized systems or peer-to-peer applications never really caught on. Some point to technical challenges or usability issues or a lack of use-cases, but I believe all of those could have been overcome with enough investment. There just wasn't enough money in them compared to centralization. (It didn't help that the only really popular systems were almost entirely used for illegal or unproductive purposes.)
And these dynamics over time are what have led to the asymmetric Internet today. The Internet was supposed to be equal, with each node capable of being a client and a server and, heck, even a router. But that's clearly not what we have today: networks hostile to P2P connectivity, increasingly powerful centralized services, and decreasingly capable end-user devices.