Not much change for Singapore, I know this because I learnt my history and geography properly, I hope you too.
Strait of Malacca has always been the busiest maritime trade route in the world continously since recorded history even until now, and at the heart of it is Singapore Strait where Singapore or Temasek is located.
Even until now most of the world's trade are performed via maritime route even with advent of aircraft, and guess what most of these trades when through Malacca and Singapore Straits. Maritime industry called these Straits the world's busiest trading choke-point. I'm not even exxagerating to say that Strait of Hormuz is nothing compared to this chokepoint, especially in the ancient time.
On top of that, more than quarter of the world's population since recorded history are living in China and India, and in between these two most populous nations are connected via maritime sea route through Straits of Malacca and Singapore.
In the old days, or most of our maritime trading history for thousand of years, we do not have engine for ships neither steam nor fuel, only for very short period recently starting from late 19th CE [1].
During most of our maritime history we use sails. People or sailors travelling between India and China, and returning back rely entirely on wind power that are based on alternate monsoon seasons. This where we got the famous saying of "time and tide wait for no man".
For one season (half a year) they used for travelling westward and another half season they travelling eastward. Either way, ancient sailors from Europe/India/China/Arab/Japan they need to stop over somewhere (read Malay Peninsular or Singapore/Temasek) while waiting for monsoon to change before returning back home. Since Singapore/Temasek at the end of this Peninsular, it's the most natural transit point for these ancient/modern sailors. Whenever you fly over Singapore take a look down to see these multitude of these ships. Although now in theory they don't need to stop for monsoon due to fuel, but realistically the ships still need for refuel/rest/transit/etc.
[1] From Sails to Steam Power:
https://www.marinmuseum.se/en/visit/exhibitions/from-sails-t...