One of the reasons JWST is expensive is its complex folding mechanism. Starship could launch a mirror bigger than JWST's in one piece.
Another reason is that they're only launching one and it has to work perfectly the first and only time it's launched. That level of reliability in a one-off product is incredibly expensive to achieve. With dramatically cheaper launches it would make sense to launch a much larger number of less reliable but much less expensive telescopes.
Another reason is politics, but SpaceX can't solve that one.
> it would make sense to launch a much larger number of less reliable but much less expensive telescopes
What if... SpaceX made up for the pollution they introduce by making the Starlink satellites look up the other way and push the captured data back to earth?
The lens and CCD would be small, but with the massive volume (and clear sky) it could add up. Like the amateur set ups using an array of consumer grade cameras.
Another reason is that they're only launching one and it has to work perfectly the first and only time it's launched. That level of reliability in a one-off product is incredibly expensive to achieve. With dramatically cheaper launches it would make sense to launch a much larger number of less reliable but much less expensive telescopes.
Another reason is politics, but SpaceX can't solve that one.