Decentralized governments: already a reality in most places, with a clear hierarchy (federal, state/province, city). Local communities aren't always formed, but can coexist

Decentralized power sources: kinda there already? The thing is that it makes more sense economically to have a small number of big power plants than spread then thinly, especially due to industry needs that can be much larger than what residential lines typically transmit

Decentralized market: I mean, open fairs and small, corner markets are still a thing, no? Or what kind of market do you mean?

Decentralized currency: crypto kinda does that? There's no central authority issuing whatever-coins. In more real-life terms, decentralized currency is deeply tied to local economy and you can look at history for how something like that used to work: small kingdoms almost always wanted to mint their own coins, then whenever conducting trade with external markets, some exchange rates would be set based on supply/demand.