Will mining centralize around one single miner? No one knows. This is why Bitcoin is still a risk.
But if this doesn't happen--if there remains more than a single miner--then the fee market does exist.
I think the point of contention is really about this conclusion.
My understanding is that it may also happen with several miners if they have an incentive to synchronize their mempools (with a mechanism like IBLT).
I ask, just because I want it to be clear to readers that this "point of contention" is about a hypothetical future scenario. And that we already know that there are hypothetical future scenarios, such as mining centralized around a single super pool, that would be bad for Bitcoin.
It absolutely doesnt. Miners already optimize for profit by centralizing in various ways. The recent SPV mining near-catastrophe is an excellent example.
Your conclusions hold under no existing and future scenario. It makes assumptions that are untenable and require absolute altruism from miners.
The crux of the issue is that miners incentives are not aligned with the network's users. The max block size cap mitigates the fact that they are expected (for security reasons) to prioritize financial profit over network decentralization. Yes, there might be no other way to align these incentives than by forcing it through consensus code.