You appear to be ignoring everything else that goes into making a company besides labor. There isn't perfect competition in the real world. Companies don't all have the same resources, customer base, or opportunities.
For example, a person doing the exact same job at Facebook is going to provide more value than a person doing the exact same job at Twitter which is going to provide more value than a person doing the exact same job at a brand new startup. The Facebook employee might be producing $1m and the Twitter employee might be producing $200k. In that instance Twitter can't pay more than $200k and Facebook has no incentive to offer more than $200k.
Or maybe a more concrete example, if I am the head of design for Ford, the value I produce for Ford is always going to be more than I can provide by myself because I have no way to put my skill set to use in a new company. I don't have access to the supply chains Ford does. I don't have access to the factories that Ford does. I don't have access to the labor market that Ford does. If I wanted to actually compete with them, it would require billions in funding behind me like Tesla.
I feel like my earlier comment has been misconstrued as "if your work generates $1MM in profit than it should be rewarded with $0.999MM in salary". That's not what I'm attempting to say at all. Assessing value is definitely more complex than that.
Additionally, yeah, it's true, competitors might not be able to realize the same value in the same space. Competitive advantages exist. Spreads between value and salaries will exist, and some companies might have bigger spreads than others because they're more able to realize value. I agree with all of this.
All I am attempting to do is refute the claim that there's no relationship between value of work and renumeration for that work ("[t]he value someone creates has nothing to do with their salary"). I don't dispute that we can create toy examples where that doesn't happen, but they aren't effective refutations of the general point.
In the short term, yes. In the longer term competition and companies/people entering/leaving the market moves demand and supply closer to something that justified by costs of production and 'value' of product.
(Economists say demand and supply are elastic, I think.)
I agree. Labor is just another input that a company requires in order to create its product. I would expect labor prices to be driven by similar if not the same market forces as goods. Excluding government interventions of course.
Labor theory of value claims that the value of X depends only on the amount of labor required to produce X. This theory doesn't explain how gold is more valuable than iron, or how $UNICORN is more valuable then this other startup. So it's a bad theory.
matthewowen's argument is not assuming the labor theory of value is true. It's just pointing out that, other things being equal, if the demand for X increases then the demand for X-makers' labor increases too; hence X-makers' wages increase.
For example, a person doing the exact same job at Facebook is going to provide more value than a person doing the exact same job at Twitter which is going to provide more value than a person doing the exact same job at a brand new startup. The Facebook employee might be producing $1m and the Twitter employee might be producing $200k. In that instance Twitter can't pay more than $200k and Facebook has no incentive to offer more than $200k.
Or maybe a more concrete example, if I am the head of design for Ford, the value I produce for Ford is always going to be more than I can provide by myself because I have no way to put my skill set to use in a new company. I don't have access to the supply chains Ford does. I don't have access to the factories that Ford does. I don't have access to the labor market that Ford does. If I wanted to actually compete with them, it would require billions in funding behind me like Tesla.