Probably not a “top” school but there are several examples of decent schools flying up the rankings and falling down a few notches shortly thereafter. Northeastern comes to mind but there are others. University of IA is a perfectly decent state school that has fallen 12 spots in 3 years. As I said, very easy to do when you are lower in the rankings. With respect to med. centers, all it takes is several competitors to nudge you out and down you plummet. It needn’t mean you are “worse” than you used to be (although it certainly COULD suggest that). What it CAN mean, in the hyper competitive environment for ratings, is that others have been quicker than you to climb to the top - or your eye is just off the ball. As I mentioned prior, UChicago might be viewing the purpose of its hospital system a tad differently than a Mayo or a Cleveland Institute or even a Northwestern.
I go back to the question - how does UChicago’s health system function now vs., say, 10 years ago? Better, worse or the same? That tells you more about UChicago Hospitals than do the rankings. However, there is no doubt that rankings are going to be generally correlated with success and $$$'s.