I think the biggest mistake was that for the production of bitcoin began to be used only with special equipment. This allowed us to create an exclusive clan of miners. It was much better when each user could have separate coins and there was no clan of miners. I think in this situation, blame the developers who are now also suffering from the dictatorship of the miners.
After 4 years in crypto I'm still surprised to see how good was the tech design of bitcoin since the very begin. Basically it was created almost perfect. Probably the only thing that Nakamoto didn't predictewas the born of a real industry around the bitcoin mining. Original plan was to allow everyone to participate in the mining process from their own computer. That was "perfect decentralization".
Then people realized GPUs can do the job much better. Still the decentralization was acceptable. Then came FGAPs and in short ASIC. And here decentralization of mining failed... : /
