HK is wealthy because of where it is. Good luck trying to replicate that in the Falklands or on some rock in the Caribbeans.
Britain was once considered a backward periphery of Europe. Japan is so geographically peripheral that it could successfully close itself off the rest of the world for 250 years.
On the other hand, there is no Yemeni/Somali equivalent of Singapore even though a lot of the world traffic must pass around them. Gibraltar is rich, but Spanish Andalusia all around it has pretty stagnant economy oriented on tourism. Panama kinda works, but nowhere near as well as, say, California or Florida.
But you still need something to leverage. Distance from population centers matters, trading routes matter, topography matters immensely as well.
Britain rose in conjunction with Trans-Atlantic trade. And so did Japan with Trans-Pacific trade and the development of the American West coast.
HK is an I/O hub for one of the largest economies in the world, it doesn't get much better.
An hypothetical Neo-HK somewhere would have to forcefully re-route the world's economy to have a chance at getting the same standing.
Admittedly, Hong Kong benefitted a lot from being the convenient middle ground where major deals between entities in mainland China and other countries could happen. However, it can also be argued that meeting in person to shake hands might not remain a given going forward.