>> We now have the capability to put up another ISS today, resupply it, and staff it, at a fraction of the cost,

Capacity to put mass into low orbit, but building a multipart space station requires far more than cobbling modules together KSP-style. Shuttle and the Canadarm(s) built the space station. SpaceX doesn't have that construction/manipulation capacity. It doesn't have the spacewalk capacity. To match Shuttle and build another ISS SpaceX would need to send people and cargo on the same flight, something that is certainly physically possible but remains logistically complex. NASA doesn't spend millions training astronauts in that giant swimming pool because they like the water.