If an ISS replacement isn't ready in time, that rests squarely on NASA for not starting the process and ramping funding sooner. This new angle that they're fine with LEO capability instead of LEO presence is just because they screwed up on lining up the next stations.
Good on Vast for not waiting. While I'm sure they'd appreciate a study contract, they're positioning themselves to be the only ones waiting for NASA to sign an actual services contract.