Bitcoin has really failed to overthrow the banks and the state. And that is because everything we do including our business activities are being monitored and regulated by the state.
No, it is because it was badly designed, that's all. Bitcoin contains several fundamental design issues. The most important is ironically what it is touted for to be important: its emission curve, sending out a lot of coins in the beginning, and going down to zero. That turns bitcoin not into a stable currency, but into a speculative asset. The second one is proof of work as consensus mechanism, which industrializes and centralizes the system in an industry/customer relationship, instead of a user community. And finally, the last one is the block chain itself, where everyone needs to know every other transaction in the world in a very specific list in full order. I would add to that the traceability of bitcoin, which make it a dangerous way of using your money because your spendings are open to the world, graved in stone. But on top of that, there are religious beliefs in bitcoin that kill it totally: the idea that the number of proxy servers of the unique chain is important, and that therefore, its size should be limited.
It is not the state's fault that a thing that is designed to be a speculative asset with clunky technology based on erroneous economic and game-theoretical beliefs, doesn't replace the worlds' financial system. However, it will take a maybe big chunk out of speculative finance and at a certain point, banks will love it, especially in combination with its buddies, alt coins, to get money out of the pockets of home-traders and believers.
But this thing was ill designed to become money, and hence it didn't become money. Apart from those places where normal money cannot go and it doesn't undergo competition: dark markets and other such things.
In fact, the reaction of states is in many cases surprisingly positive towards including bitcoin in the legal system. In many countries, it is not illegal to possess crypto. If you declare them correctly, and you use legal exchanges in a transparent way, bitcoin and other crypto are in fact not stopped by the states. Nobody stops you from using bitcoin to do payments. But it is simply not practical, and you are obliged to speculate on bitcoin if you use it, because it has no price stabilizing mechanism (on the contrary, bitcoin has to "rise" with adoption, which is an economically crazy idea for a good currency). There's no point in using bitcoin as a currency, it's a hassle.