Most of the problems of Bitcoin are solved by centralization. Reversibility, transaction speed, increasing and decreasing the supply. The problem is that centralization creates an investment contract. We already have a medium for exchanging those. It's called the stock market. Bitcoin operates out of the control of any government or regulation. Thus, the decentralization imposes limitations on its design.

XRP tried to make a centralized cryptocurrency that solved those problems and now the SEC is basically telling them they have to give all the money back because it's an investment contract.