The ISS is primarily a jobs program, and secondarily a way to maintain our manned spaceflight infrastructure in case we ever decide to leave LEO again. The scientific research is barely an afterthought.
I consider it an excuse for Russia to keep their rocket scientists employed after the fall of the soviet union. Nobody wants a starving rocket scientist driven by desperation to take a job designing ICBMs for some evil dictator.
It's more important to preserve the infrastructure rather than actually maintaining organic manned spaceflight capability. If we have all the infrastructure intact then the capability can be spun back up in a few years just by increasing funding. But once the industrial base disappears then it's effectively gone forever.
