That isn't how salaries work. If there are many people who are willing to do the work at a given salary, it doesn't matter if the company earns 5x from that lab

That isn't how salaries work. If there are many people who are willing to do the work at a given salary, it doesn't matter if the company earns 5x from that labor. Supply and demand are obviously not the only factors, but they are very important and must be considered when looking at compensation for employment.