It is true over a longer horizon, you lose that job opportunity to a better employee they can maybe excel and increase the pie and make it more likely they want to hire you or someone else, but over the short run I think it can be approximated with a zero sum game, there's one job opportunity (that you covet) and your victory comes at your competitors' expense and vice versa.

This may be less clear in tech and for us cause the boom times have been very good, but imagine a scenario like the big company in your small town is hiring, and that's your path to potentially a steady income. You don't know when they are hiring again, and your town's opportunities are limited.

In any case the idea that there aren't zero sum competitions in life (another example is competing for a certain romantic partner, something I didn't even mention which i realize is implicitly perhaps behind a lot of this among young people) is a myth that a lot of people push because they simply don't like competition and competing I think. Not only are there zero sum or approximately zero sum games in life, they are among the most impactful ones.