Two hypotheses are the classic stories about being killed by your own success. One has to do with increased risk aversion and one has to do with dilution.
There’s also a story where factors external to the nature of The Florence are what cause it to stop being a Florence. If Florences require a world-class high-profit discipline and a world-class cultural discipline is true, Economic forces that kill the world-class high-profit discipline will also kill the Florence.
These need case studies