That was insignificant compared to what else he said, which is that ULA is banned from using the RD-180, which powers the Atlas-5, from launching US military satellites. It is presumed this also means that we'll no longer get any RD-180s. Perhaps the Administration shouldn't have targeted his personal finances without considering the consequences.
I'd wager that the DoD has some classified backup plan to launch their satellites we are un-aware of.
Regarding the ISS - if Putin is still in power in 2020 and still not wanting to play ball with the ISS - at least for US astronauts we're fucked. However, I'd imagine he would not want to alienate the rest of our European partners involved in the project as well?
Aside from the space ramifications regarding these types of decisions - there are a lot new Russian billionaires I'd imagine who aren't happy with Putin's recent political decisions that may affect their personal wealth since how they play with the West has been affected as well.
In short, despite the fact that Putin wants to believe that it's 1974 and he can make unilateral decisions for Russia - old Soviet era sytle - I'm betting he has less power than we are led to believe and cannot make decisions in a vacuum nor without the support of his weatlhy friends.