What's the path-dependency-ness of life? Like, once you have carbon based life to what degree does it preclude silicon based life from evolving? How often doe

What's the path-dependency-ness of life? Like, once you have carbon based life to what degree does it preclude silicon based life from evolving? How often does a feature evolve sui generis when the nich that the feature exploits is already filled? Clearly it happens sometimes so if you've got a good enough angle you can step into something that's seemingly already covered. For all that after several billion years it's just carbon based life forms in these parts. You'd think that there must be some area where silicon based life would provide an advantage. Unless it's a case that carbon based life is an overwhelmingly superior product but on some hypothetical world it's simply filled with silicon and there's virtually zero carbon.