Your link says that US had no homegrown option, when it used russian rockets.

The only part that matches “because cheaper”, was atlas rockets using soviet engines, but that also had additional reasoning of keeping russian rocket engineers away from iran and north Korea.

So overall, US definitely will subsidise a US company. (If not spacex, then other company which demonstrates competence) Strategically it is a must have capability. If you depend on others, you open your self up for bunch of risks.