They've signed a contract with the US government, now they have to honour it. Legally, they can't cancel it without NASA's agreement. They could try to force NA

They've signed a contract with the US government, now they have to honour it. Legally, they can't cancel it without NASA's agreement. They could try to force NASA's hand – but that would severely damage their chances of getting any other US government contracts in the future-not just NASA, but the rest too–including the military, which makes Boeing roughly 10x as much money as NASA does. So the cost of trying to “cancel” Starliner would be vastly more than whatever they are losing on this particular contract. Poor Boeing just has to wear it.