So one of the problems I have with your "logic", is that half of the time you come up with these 1 + 1 equal 2 equations that ignores some other factor or is based on multiple assumptions, some of which can be flawed.
Well, I invite you to point them out.
Outcome U is only accomplished because X "put" the decision into the hands of Y.
Nobody "put power" in the hands of anyone. This is a dynamical system, with its different behavioural laws. Like in nature, nobody "put the power of decision in the hands of this or that species". Or like the solar system: the laws of gravity tell the planets how to move. Nobody "gave the sun the power to decide where the planets go". When you study the system, you try to find the different behaviours of the components as a function of the behaviour of the other components in the system. Once you understand that, you can try to predict how any change in behaviour of one component, influences the behaviour of another component. That's all.
I also find your statement that full nodes are not representative of the market truly perplexing. While we don't know the entire makeup, it's clear that a good portion of those full nodes are exchanges, payment processors, companies, traders and users. So how one then can possibly say that they're not representative of the market is just.. well I can't think of a good word for it.
Well, there are more than a million of bitcoin users. There are about 7000 full nodes. Clearly they are not representative. As one can start up as many nodes as one wishes, and as this is totally not related to what one does on the market, it must be rather clear that there is no causal link between what happens on the market, and what nodes are running what, no ?
Take exchanges. I think we can agree that exchanges will see a mega profit if ever bitcoin splits in a hard fork, because many users are going to trade one of their coin copies, for the other. So even if an exchange is now only running a node that goes with, say, "fork A", of course they will quickly fire up a node that goes with fork B to be able to have their customers trade both of them (and have them reap in the fees on all of these trades). So a big exchange having a node that only runs protocol pre-cursor A, doesn't mean, at all, that they won't start another node for fork B.
As to users, suppose there is a hard fork by miners (that was YOUR proposal). Do you really think that if you are a whale, and you have, say, 100 000 BTC, and after the split, you have now 100 000 BTC-A and of course also 100 000 BTC-B, that you will *refuse the value of your BTC-B holdings* by refusing to transact on chain B ? Do you think people will "throw away free money" because they are now running a node with only one software flavour ?
I suspect what this comes down to is, if you are predisposed to believe (or want it to be true) that full nodes have no power, then all they can do is "influence" through action as you believe. But others believe that the ability to perform an action that "influences" things the way you want is, ultimately, power.
But this is a purely technical question, which has a reasoned answer, it is not a matter of belief. My "belief" comes from argued thinking about what happens or what is likely to happen in different scenarios, not from any predisposition to anything. I'm trying to understand how this system works in reality, what components have influence on what, and for that, I suppose that these components change their behaviour, and I try to find out what are the propagated consequences of this change in behaviour. That's how you find out how something works.
As for your plastics guns analogy. When you throw things like that out there I end up questioning your sincerity. You take some non applicable analogy and then basically imply that anyone that thinks this is true is not logical. i.e. implying they're "crazy". Throwing in the "I'm not being political" prior to that further makes it appear that you're not sincere and are just trying to advance some agenda.
These discussions always end up like that: no logical argument. (*) I wonder if in bitcoin land, someone actually thinks logically. As I told you, I saw a claim that seemed to go against how the bitcoin dynamics was established: proof of work was established to avoid any Sybil attack by nodes. As such,
anything that doesn't do proof of work was designed not to have any influence on the system. But of course, it is not because it was DESIGNED that way, that it WORKS that way. So, even though bitcoin's design was such that non-mining full nodes were not to have any influence, it could still be the case that they DID have, in practice, some influence. But when analysing on how they could enforce anything, it seems that the design of the bitcoin system was correct: non-mining nodes, do, indeed, have no influence.
So it is quite strange that the argument to the opposite is even used. Bitcoin was explicitly designed NOT to let any influence to full nodes, and moreover, if you think about it, and try to find out if, nevertheless, they COULD have some influence, you find out that all arguments point out that, no, they don't, as was expected (but not proved initially) from the design.
Anyway. I think it's safe to say that neither of us will be able to convince each other one way or the other.
You can perfectly well convince me with a logical argument: you describe a situation where the full nodes enforce their protocol upon the block chain - which is after all the claim that you believe. If every step in your argument is correct and plausible, then I'm convinced, because then, the confrontation of your arguments with mine will show where one of us is wrong. That's how science is done, usually.
(*) edit: the "plastic gun analogy" was of course not a logical argument. It was an illustration of how I saw the situation. The plastic gun analogy didn't prove anything, the real proof was earlier. Once it was established by logical reasoning that there's no significant way in which full nodes can enforce their protocol, it makes them look like plastic guns. But not before of course. Analogies are not logical arguments, and it wasn't used as such in this case. They are just illustrative, after the logical argument has been given.