I understood what you meant by "free" but you seem to be discounting the high cost of making that choice.
You can examine the language ecosystem as a market but if you do you see immediately that it is inherently a lock in market.
Once you choose a language it's very high cost to change languages.
It's also high cost to choose a language that's not already popular, recruiting is more difficult and you will not have as much 3rd party library support.
So you have both "lock in" and large advantages for existing large players. Sure, it's technically still a "free market" because it's not regulated by the state but this kind of market doesn't have the behavior you are assuming.
What evidence do you have that these kinds of markets optimize for "better" languages?