However I do think there will be a Web 3.0 and it is going to come about when processing power, battery life, efficiency, global internet, and easy power generation all start reaching a critical point. Combine that with a general psychological backlash toward mega surveillance, concentration of power in massive corporate entities, and mass automation and we will be ripe for a world where low tech becomes stylistically cool again but with just the best of the tech world when wanted.
If you plucked someone out of ancient Rome and brought them to this society a lot of the technology might really seem like magic. I am imagining independent adhoc networks that can be easily setup to servicing a small remote village completely disconnected from the outside world and just as easily instantly connect that village to a high speed global network. And it all runs off a few solar panels or some other source of cheap power.
The decentralization of Web 3.0 will come about when we have the hardware to actually do things like that. When the ratio of cheap power generation to power use blows away what we have now. Who knows what crazy stuff people will come up with!
Or we could go the Wall-E route and it all goes to shit
Lets face it though - version point 0 is often a buggy mess. Bring on Web 3.1 !