Starliner isn't the rocket, it's the vehicle which rides on top of the rocket and could in theory be carried by multiple different rocket types. The article says Boeing is still considering keeping the SLS in-house for the moment, although that one might be killed by NASA or Congress instead.
Starliner is a reusable spacecraft. Since it lands in the desert, it should be easier to refurbish than Dragon, which lands in the sea.
But all that is mostly theoretical unless Starliner becomes a reliable spacecraft.
