> The question is whether those markets are not already adequately served by Falcon 9

What does that even mean? Almost every single Falcon 9 customer will prefer launching on Starship if/when it is available, because the cost will be much lower. A very small segment who have payloads that are exactly Falcon 9 sized and want a very particular orbit might still be better served by F9, but maybe not.

Beyond that, much lower cost unlocks previously untenable opportunities that you have not sufficiently imagined, as stated earlier.