If there exist jobs that produce $1MM in value but that have a going rate of 200k, then there should be more of those jobs: either the company doing the work should expand, or it should have competitors. This will lead to increased competition to hire, which means higher wages. The increased number of jobs might generate downward pressure on the value produced by those jobs (since the output is now less scarce), and the increase in salary should increase the number of people who want to work in the field (which would dampen the salary increase), but we should ultimately reach some sort of equilibrium. The fact that tech companies bemoan how hard it is to find employees suggests that we aren't at this equilibrium.
To give an analogy, your explanation is akin to when people observe that the price of a good is based on the competitive market, and that the cost to produce merely provides (in most cases) a floor to that price. However, that's only part of the story: in a well functioning market large spreads between cost to produce and price encourages competitors to enter the space, which leads to lower prices. There may be delays, and there may be exceptions, but generally the function of competition is to reduce these spreads. Likewise, we should expect competition to reduce the spreads between job value and job salary, generally by increasing salaries and lowering values.