Cloud computing already works by decentralizing dynamic state with high resilience to failures. For instance, servers might be allowed to remain inconsistent for awhile (since there is no single point of failure to tell them what their state should be), synchronizing "eventually". Of course, then the system is forced to deal with the possibility of multiple versions and trying to figure out the actual order of operations when there's no common time server (since a clock would itself be a single point of failure) but there are algorithms for making that work as well.

Since we now have these technologies and other technologies like security protocols, I think we are at a point in history where decentralizing the web is plausible and maybe even a straightforward thing.