(Edit: "limit order" looks like technical jargon. If so, I don't know what it means. Maybe you didn't say what I thought you said)
In your example, it looked like you wanted your 500 share for something else than selling them. So you're talking about "real transactions (with non-speculators) at the boundaries". So yes, those transactions are a useful service provided to you by the speculators. I'm not denying that.
On the other hand, your wording seems to imply that most transactions are of this type (non-speculator with speculator). As far as I understand the system, they are not. If the OP is to be trusted, the vast majority of transactions are between 2 speculators trying to outsmart each other. Do we at least agree on that narrow point?
My second point is that a such a transaction (between 2 speculators) is zero sum. Locally, because whatever the first speculators won, the other lost. And globally, because wherever the share is, it could still be sold to a non-speculator. Making the transaction between speculators doesn't make it any easier. I'd say it could make it harder, for the non-speculators now have to buy the share faster than the speculators (or pay extra to have traders do it for them). Seriously, where is the value in that?
Now maybe a good speculator tends to provide a good service to non-speculators. However, they are not selected by the quality of the service they provide. They are selected by their ability to rip each other off. How quality of service arises from such a cut-throat competition is mysterious to me. (Usually, we compete for quality of service directly, so the connection is obvious. Speculating is not the same thing.)
I think we are getting closer to understanding here. You're kind of quibbling over the definition of value in your other post - someone can provide a "valuable" service even if it isn't currently being used (by your 'real transactors'). I might sleep better at night knowing that if I want to liquefy my investment in Apple tomorrow, I can do so without having to worry that nobody will be there to take the other side of the trade, that I'll have to pay an enormous spread or be left holding a position I want to be out of. An international corporation can be more confident of planning their cashflows knowing that the FX market will always be liquid, and will be quoting at most 2 ticks wide in the majors 24 hours a day every day. This is the oil of an economy, the freedom to allocate capital when you want, where you want and pay the smallest possible friction costs to do so.
Many things in our economy can be described as a zero-sum game. Society only needs so much of any given good, and at the retailer level you aren't involved in increasing demand.
Two corner stores might get into a price/advertising war, but let's argue that there is still only a fixed amount of product they can sell to a small community. So advertiser's get fat on fees (in our case, exchanges do). So what is the point you ask? Evolution, competition, it can only be good for the consumer. You still haven't disputed that by the way, the consumer wins don't they? How could they possibly have lost? It takes a tin foil hat to think that it isn't better and cheaper to invest now.
" they are not selected by the quality of the service, just ability to rip each other off" - people have a bit of a naive view that there are some sort of magical harlem globetrotter moves you can pull on an order book. The mechanics are dead simple I'm afraid. It isn't chess, not even checkers. You can't even see the other participants, everything is anonymous on the exchanges I've dealt with. Spoofing is illegal, and that is about as clever as it gets. Very little you can do to make your algo better will put it at odds with providing a better quality service.
To prove that, remember the two types of algo. If I write a liquidity provider that doesn't offer a tighter spread than the competition, I will miss out on trade flow and make little or nothing. If I write a liquidity taker that has an opinion that is wrong about the correct value of a security, someone else who is right will smash me. So effectively we are selecting for more liquidity, tighter spreads, and more accurate prices reflecting available information.
My definition of value is simple: something is valuable when it manages to raise people's utility functions (right now, that's about as rigorous as I can be). A trade that happens to be closed by a plain old investor is valuable. If it's another speculator, however, the value is zero. Only consequences ultimately matter.
But, if I got you right, the anonymity of it all mean we cannot separate the two… hmm… Then we've got to multiply the potential utility of the trade by the (quite low) probability of it being closed by a non-speculator. Still valuable, but much less. And I'm back wondering to what extent this is worth the (collective) effort. You did change my mind a little, though. I'll need to learn more.
> You still haven't disputed that by the way, the consumer wins don't they? How could they possibly have lost?
The consumer winning does count as creating value. However there are 2 parts in the retail store competition example: the part where they compete on quality, price, diversity… and the part where they pay fat fees to the advertiser. The first part benefits the consumer, the second just add inefficiency in the loop: if both stores could only agree to not use ads, everybody would win.
When Pareto Optimum and Nash Equilibrium are at odds, life sucks.
In your example, it looked like you wanted your 500 share for something else than selling them. So you're talking about "real transactions (with non-speculators) at the boundaries". So yes, those transactions are a useful service provided to you by the speculators. I'm not denying that.
On the other hand, your wording seems to imply that most transactions are of this type (non-speculator with speculator). As far as I understand the system, they are not. If the OP is to be trusted, the vast majority of transactions are between 2 speculators trying to outsmart each other. Do we at least agree on that narrow point?
My second point is that a such a transaction (between 2 speculators) is zero sum. Locally, because whatever the first speculators won, the other lost. And globally, because wherever the share is, it could still be sold to a non-speculator. Making the transaction between speculators doesn't make it any easier. I'd say it could make it harder, for the non-speculators now have to buy the share faster than the speculators (or pay extra to have traders do it for them). Seriously, where is the value in that?
Now maybe a good speculator tends to provide a good service to non-speculators. However, they are not selected by the quality of the service they provide. They are selected by their ability to rip each other off. How quality of service arises from such a cut-throat competition is mysterious to me. (Usually, we compete for quality of service directly, so the connection is obvious. Speculating is not the same thing.)