[stymaar]

The miners don't need “node runners” to get access to other miners mined block. That's not how the bitcoin protocol works at all.

In an ideal world the best non-miners can do is prevent some transactions by preventing them to reach the mempool, but you're not going to block an exchange this way either.

The bitcoin protocol is actually very friendly to centralization, the only mechanism that was supposed to prevent it was the PoW, which failed because ASICs exist. And as a result, in practice it's been very centralized for more than a decade now.