Singapore is just a temporary arrangement. There was never any long term plan in the first place.
That is where most people got misled by LKY. He instinctively knew Sg could not survive in the long term without the hinterlands of Malaysia and Indonesia.
As these neighbours developed, they no longer needed Sg as a port of trade, so LKY had to switch to manufacturing and now financing and further investments into being hub-centric.
Sooner or later they will develop their own industries and Sg will be left with growing the economy by only increasing the population. Which is what we are seeing now.
So really we are at the last phase of development which may stretch decades.
So where was the mistake?
Ans: Trusting politicians. Especially sly cunning ones like LKY. See how he installed his son as PM? Is that no different from an African despot's effort in continuing their plunder?