I think that this is the kind of cosy picture we would like to believe, was sold to us, and is supposed to supplant "corrupt banks and states with power structures". The naked truth is that bitcoin contains design "features" that has installed a very similar power structure. Yes, there is a symbiosis, but that symbiosis is very similar to every commercial relationship between a business and a customer, and has partly an aspect of predator and prey too: it is a balance of power.
However, in that ecosystem, non mining full nodes are not players.
The two "species" are:
- the miner industry: which is a two-tier system: the "industrials" who are the pools, and their subcontractors, who are the mining hardware owners. Their product is a block chain. They obtain fees and block rewards on it, which they sell to their customers.
- the customers: the bitcoin users, who transact, hodl, speculate, pay, gamble, exchange, .... do whatever they want to do with the tokens (bitcoins) for which they need a secured ledger: the block chain, sold to them by the mining industry.
This is the fundamental business model of bitcoin.
Now, the miner industry is, so people say, not supposed to be centrally organized. This is not certain, because we saw on Litecoin how centralized this was: a few guys in a meeting room could change the segwit adoption from less than 50% to 95%. That was, in other words, a kind of meeting of the board of governors of the Litecoin mining industry. But maybe bitcoin's industry is less centrally organized.
What people always point out is that the industrials have not the full power. No, of course they don't. They have customers, and they need their customers to buy their product. So of course, industrials want to get the most out of their customers. On the other hand, customers can vote with their money, if they don't like the product sold to them by the industrials. But there's a caveat: to be even able to use their money, customers have to use the industrials' product.
Now, this image is less attractive than the cosy one where "you are your own money's boss". After all, it is not so different to what we're used to with banks and so on, in the end. So we like to think that, by running some software in our basement, we have something to say. I suppose the non-mining myth is part of that.
It used to be true, that non-mining nodes played the role of "validator" of *propagated blocks*. That was when there wasn't yet a whole mining industry, and miners were distributed amongst the whole network, didn't know one another and were manifold. In that case, a miner could only mine on a block that he got propagated through the P2P network, because he didn't know where it came from. Any block not to the likings of a large majority of P2P nodes would then simply not propagate that block, and so no other miner would even receive it. The non-mining nodes acted as a kind of propagation filter between mining nodes, and mining nodes were dependent on them to obtain the blocks on which to mine.
But that is not the case any more with pools. Pools know one another. They are not manifold. They want one anothers' blocks as quickly as possible. So they don't let Joe's full node in his basement filter their communication. From the moment that the miner nodes form a back bone, the P2P network is not a filter any more, because not necessary any more in the propagation of blocks from miner to miner. That's when they lost their last grain of power. Mining became industrial, and the split between industrials and customers was complete.
But this was baked into the design of bitcoin from the start and understood by Satoshi from the start.