Until now, every kg we launch has been horrendously expensive. So all things in orbit and sent to other planets have lots of expensive design features to reduce weight or to reduce size in the fairing.
StarShip is so huge and the reuse will be so cheap that it's going to be 100x or more cheaper. We could send heavy equipment into space and on to other planets that just didn't make sense before.
Once Starship can land 100 tons on the moon, the question isn't "what can we fit" but "how do we fill all this capacity usefully?!" So the science objectives we can achieve grow enormously.
The viability of the Starlink constellation depends on getting large numbers of satellites on orbit quickly. And the newest generation of Starlink birds are too large to fit in the Falcon 9 fairing.
