A blockchain is not some type of magical 8th wonder of the world.  All it is is a ledger that requires a focal point for convergence.  The focal point is always something like stake, raw hash power expenditure (which is nothing more than externalized stake in practice), or some other variable that can be quantified where I can say that I have more of it than you do.  Where exactly do you see "decentralization" arising from such a paradigm?  You would need to be a fool to think so.

The only way such an idea would not be laughable at face value is if everyone who uses the system was required to be a miner, but that's obviously not possible due to massive monetary and intellectual capital required in creating chip foundries and the fact people can corner said technology and not share it.  Even if you could design it that way, the Pareto principle would still destroy it decentralization-wise anyway.  It's 100% not possible to create a decentralized digital currency.