[Fin_Code]

The current Falcon rocket always expends a stage and lands a stage. Starship will land both stages. Also Starship is far larger and in rocketry there is something called the square cube law that means bigger is better. So its far more efficient. That leads to far cheaper mass to orbit costs.

[cryptonector]

In order to land not just the first stage but also the second stage more fuel will have to be carried on the ascent phase just to enable the recovery phase. This then necessitates weight savings elsewhere to avoid payload to orbit being cut way back. SpaceX chose to remove the landing system from both, the first and second stages (both because, after all if you can eliminate the landing system from one stage then you can eliminate it from the other).

This and other weight savings will enable high payload to orbit in a fully reusable launch platform.

Landing without legs requires something like this catch system -- something never done before, and clearly very difficult to do.