"Blockchain provides satisfactory answers to all those problems." - mostly by hand waving. The blockchain model works in the case of cryptocurrencies - because

"Blockchain provides satisfactory answers to all those problems." - mostly by hand waving. The blockchain model works in the case of cryptocurrencies - because it is subsidized massively by the block rewards. It is very elegant solution - every party can join the system and leave when it wants, no need for any contracts. It is also very surprising that this can be done and that ignited the imagination, but none of the non-currency blockchain projects that I have heard about want to use that model - because of the enormous cost. They want something called 'private blockchains' with no PoW or any other mechanism relying on coin minting - but if the blockchain maintenance is not subsidized by new coins - then you need contracts for that. And it gets much less elegant. Blockchains are also very complex systems with huge attack surfaces, because they are build around complex incentives structures. Private blockchains don't have the elegance of the public, free to access for everyone blockchains, but they still have the complexity.