I believe it when there's a replacement launched, it's been about to be decommissioned for the last 2 decades with the same idea that there will be a commercial station to replace it and it always gets pushed back because space is still too damn expensive for anyone other than a government to put people up there. Maybe NASA's hand will be forced by the slow degradation of the structure from heat cycling causing leaks…
To put in in perspective, the ISS required 36 Space Shuttle launches at a cost of $1.5B per launch ($54B). For that cost, assuming a pessimistic cost for Starship of $10M per launch (5,400/4 launches), you could launch 1,350 International Space Stations for the same price as the ISS cost to launch flying on the shuttle. To me it sounds not only realistic that we would launch a replacement but surpass it by 100x or 1000x.