The Bitcoin white paper says:
The proof-of-work also solves the problem of determining representation in majority decision
making. If the majority were based on one-IP-address-one-vote, it could be subverted by anyone
able to allocate many IPs. Proof-of-work is essentially one-CPU-one-vote. The majority
decision is represented by the longest chain, which has the greatest proof-of-work effort invested
in it. If a majority of CPU power is controlled by honest nodes, the honest chain will grow the
fastest and outpace any competing chains. To modify a past block, an attacker would have to
redo the proof-of-work of the block and all blocks after it and then catch up with and surpass the
work of the honest nodes. We will show later that the probability of a slower attacker catching up
diminishes exponentially as subsequent blocks are added.
This, Satoshi (who doesn't really matter anyways I guess?) claimed that for Bitcoin to function properly you need a majority honest nodes.
There are multiple behaviors one can describe as honest, and economically rational or optimizing is not necessarily rational.
For example, if I run a shop that takes rain checks, but I sell an item to a higher bidder who didn't have a hold on the item, that is not honest, but it may be selfish profit maximizing.
Satoshi said an honest majority is required for the chain to be extended. Honest is not really defined though. Honesty, in my definition, is that you follow a pre specified rule, rational or not.
It seems a lot of the RBF controversy is that Protocol developers have aspired to make the honest behavior also be the rational behavior. This is maybe a good idea because, in theory, if the honest behavior is rational then we can make a weaker assumption of selfishness maximizing a parameter.
However, Satoshi did not particularly bound what aspects of honesty are important for the network, because there isn't a spec defining exactly what is honest or not. And also as soon as people are honest, you can rely on that assumption for good effect.
And sometimes, defining an honest behavior can be creating a higher utility system because most people are "law abiding citizens" who might not be short term rational. For example, one might expect that miners would be interested in making sure lightning closes are "accurate" because increasing the utility of lightning is good for Bitcoin, even if it is irrational.
It seems that the NoRBF crowd want to rely on an honest majority assumption where the honest behavior is not doing replacement if not requested. This is really not much different than trying to close lightning channels "the right way".
However, where it may be different, is that even in the presence of honest majority, the safety of 0conf isn't assured given the potential of race conditions in the mempool. Therefore it's not clear to me that 0conf working well is something you can drive from the Honest Majority Assumption (where honest includes first seen).
Overall, it might be nice to more tightly document what bitcoins assumptions are in practice and what those assumptions do in terms of properties of Bitcoin, as well as pathways to weakening the assumptions without compromising the behaviors users expect the network to have. An "extended white paper" if you will.
It's somewhat clear to me that we shouldn't weaken assumptions that only seem local to one subsystem of Bitcoin if they end up destabilizing another system. In particular, things that decrease "transaction utility" for end users decrease the demand for transactions which hurts the fee market's longer term viability, even if we feel good about making an honest policy assumption into a self interested policy assumption.
A last reflection is that Bitcoin is specified with an honest majority assumption, but also has a rational dishonest minority assumption over both endogenous (rewards) and exogenous (electricity) costs. Satoshi did not suggest, at least as I read it, that Bitcoin works with an rational majority assumption. (If anyone thinks these three are similar properties you can make some trivial counterexamples)
Cheers,
Jeremy