What a weird take. It's good for the employee to get fired because then the company doesn't have to pay them competitively?
The quality of the work isn't as important as the margin between the cost of labor and the income earned by it.
To be the best and still pass that test you need to be so good that it makes up for your higher cost, which is a more difficult bar to pass than being good enough but being cheap. Also there's an upper limit anyway where no matter how good your margin is, your cost can't be justified, since "local market rates" apply downward pressure, as well as an upper limit on how much clients are willing to pay or the size of the market you're selling to or temporal factors e.g only a certain amount of widgets a country can consume in a month.
There is no labor under capitalism without significant profit margin, and always the profit extractor (employer) is trying to get the most profit for the least cost from the profit generator (employee), who is in the opposite position, but at a disadvantage since they are a human who is influenced by things like social pressure, a desire for recognition, and the natural human tendency to be good at something and do it well. The employer isn't human, it's just a profit generating algorithm, and so only cares about such things insomuch as it can leverage them to increase profits.
There's other factors in play as well though that corporations can't include in their algorithm since they're purely selfish actors which results in macroeconomic catastrophes, so for example if wages get too low then people don't buy things anymore which drives down profits from selling which forces wages down lower and so on until economic collapse.