no client which deals with engagement with the blockchain provides an estimated cost versus the resources that you have in your pocket before you commit a post or reply.

You are correct to my knowledge. I'm not a UI developer, but I would imagine that some are working on this.

the current 1/10 RC cost adjustment is long-term untenable to do what the system is supposedly intended to accomplish – actually charge people in line with the amount of resources that they consume for using the platform

It is a valid perspective. I am undecided on this and still evaluating it.

but everything that has come down from on high suggests that the more restricted resource environment is what is intended because some of the side effects are thought to be beneficial

Maybe so, but to my reading this post didn't say that. It read as more balanced to me, expressing a desire to want to balance growth and usability with resource sustainability. Easier said than don't, to be clear.

The most recent post by Steem Inc. was fairly explicit that the 1/10 RC adjustment was achieved without having to do a blockchain replay because the transaction costs were witness adjustable

What they meant was that this could be accomplished by witnesses updating their software to 20.5 (from 20.4) and it did not require an immediate replay to have some corrective effect (but all witnesses did eventually perform a replay to avoid certain edge cases). This is distinct from witness parameters (such as the new account fee) which can be updated without a software update.

This particular update did not require all non-witness nodes (such as those used by exchanges) to update, although some nodes (such as those used by the steemit.com web site) did indeed need to update and replay.

They were prefilled to 90%, and that was in no way anywhere near what was necessary to allow continued function of the blockchain

I think you are referring to the original pre-1/10 situation. In that case, the issue was not one of prefilling (which both versions did) but simply that the budgets were too low. As you state above, it is not really clear (at this juncture) whether the budgets are sustainable. In any case the pre-filling to 90% doesn't change the long-term equilibrium, it only helps get there faster (otherwise we would have to wait weeks for the pools to fill).

Telling me that "there will be further adjustment to equilibrium but only around the edges" in the wake of an order of magnitude adjustment to costs are just words

What I'm saying is that the formulas adjust over a period of days to weeks, and we can see that rate at which they are adjusting. So large adjustments from here absent code changes or dramatic changes in usage appear not terribly likely.

"further adjustments are coming but I'm sure they're going to be small" is high comedy

Again, I am referring to the automatic adjustments. Adjustments in the form of code changes may very well not be small.

I'm firmly of the belief that more changes are inbound but they won't be just around the edges. The entire mechanic has to be examined

I will not dispute that point at all. Generally speaking I agree with it.