Be that as it may, it is diametrically opposite of what was pumped out for newbie consumption when they were trying to rope people in.
That's not true. Bitcoin is correctly marketed as "decentralized". It's not marketed as "every single human in the world gets an equal say forever no matter what". Various aspects of bitcoin can (and probably will) consolidate significantly and yet remain far more decentralized and far better than alternatives. And that's what matters; remaining on a different level than the legacy financial system.
Maybe you remember the dusty old term 'peer-2-peer'?
I got my share of abuse for proposing that it should be deprecated as a sales pitch before it became a total joke since that is the way things are heading.
I think people forget that the P2P network is just as much a part of Bitcoin's protection mechanism as block mining is, if not the most important part. And the P2P network remains quite decentralized (I currently have 2 nodes running, one at home and one in AWS and neither mine for blocks)
The blockchain created by miners functions as the network wide official historical record. It enables newly joined nodes to compute the current ledger state to join the network, and prevents a poorly connected network from having separate node groups diverge.
But it is nodes on the P2P network who: Validate transactions, Transmit transactions across the network (and to miners), Block double spend attempts (the network quickly agrees on the "first" spend), Validate mined blocks and Monitor/track re-orgs.
We could have a single miner left, but the P2P network would still function as a mechanism to keep that miner honest. As long as that miner included all valid transactions from the network's memory pool and did not issue block re-orgs then Bitcoin is OK. If that miner tried to a) reject certain transactions (never include certain trans in blocks), b) issue double spends (insert trans into a block that conflicted with the P2P's selection), or c) re-write history (by re-organizing farther than 1 block back), then any of this would be very visible to the P2P network and the network could collectively decide on a more honest blockchain mechanism.
Mining can become more centralized because their actions are very visible and more importantly validated by decentralized peers, which any of us can participate in. That is the meaning when we say Bitcoin is decentralized, it is that we all can participate in the network's validation, mining is one aspect of that validation but not the only aspect.
As a thought experiment try comparing Bitcoin with only a few miners plus the P2P network, to either the FED or the London bullion depository. Even in that scenario Bitcoin is infinitely more visable and verifiable than either FED dollars or gold bar existence/ownership.