I understand there is a "Russian side" and an "American side" to the space station, and a number of modules were designed and built by the Russians. From a systems/engineering perspective, can the ISS keep going if the Russians decide to shut the lights off and go home on their side? Or would the remaining partners have to take over the Russian side to keep the whole thing going? And if the Russians go home, who provides the technical support, spare parts, etc. for the Russian modules? Not sure I'd want to pick that project up!
And as Wiggy points out, with the US focus on commercial space, is there the interest/finances to do so by NASA, SpaceX, or anyone else?