True, but not really in the way you describe. The US is the main (often, the only) customer of US space companies. If you control the money, you control the operational agenda. If you want a a new ISS? Just write up the contract.
The way in which you don’t control the agenda is only inasmuch as the strategic interests of the space company diverges from those of the US govt. But typically, with outsourced high-value work, vendors will evolve to MORE closely align to their big customers. (It screws the small customers often, but hey, the govt isn’t small).
The issue in my mind is much more value extraction & leverage, but as long as there’s multiple players (including an in-sourced option), I don’t see how it’s a problem.