That was always meant to be transitional. Also, as China marches forward, Hong Kong loses its leverage over Beijing. Now it's just one of a dozen HK-like cities for China. It went from "little prince" to "problem child".
Certainly a factor: IIRC Hong Kong's GDP versus the mainland has gone from 20-30% to 2-3% in the ~28 years since the handover, as the mainland has modernized.
While that still puts in the ballpark of "top 5 cities", it's not quite the same (relative) prize as before.
