From a recent parliamentary session:
What has not changed is that in Singapore’s land-scarce context, we do not have the luxury of space to develop a comprehensive network of dedicated cycling lanes on our roads. Our focus remains on making it safe for various road users to share the space we have.
The fallacy is in assuming that the introduction of bike lanes cannot be made at the expense of existing car lanes. But bicycle lanes transport more people per unit area of road space. So it would in fact be a better use of land to replace a car lane with a bicycle lane. If you are short of land, it should be all the more important for you to switch from car-friendly American-suburb-style urban planning to dense-population-oriented European-style urban planning. Only cities with lots of space for sprawl to spread can afford to have swathes of highways.
Note again the assumption that prevailing pro-car infrastructure is sacred.