But... this is both speculative and marginal. If Starlink needs more hardware, they can ramp up Falcon 9 rocket use, which is already partially reusable, and will continue to increase reuse. Starship could drive down launch costs, but it can't reduce the cost of the satellites themselves. You'll hit a floor where it could reduce costs, but not remotely enough to justify it.
Starship is on a completely different playing field. It strives for a VERY large payload with a VERY large fraction of reuse. This makes no sense unless actual people are riding on it at some point. The demand for orbital transport is not enough otherwise. It only makes business sense by assuming some future activities will happen which will bring in a massive amount of funding. This is beyond conventional business risk, this is a leap of faith.