I was there for nearly two weeks and explored as much as I could. That was my impression.
I just checked, and Singapore actually does have the lowest fertility rate in the world, by a large margin: 0.83. The notorious infertile Japan is at 1.41. I think makes a difference to the culture.
You actually need to see where people live, hdbs to see schools, playgrounds and such. The low fertility rate is common amongst developed countries. On the other hand, the government has explicit policies to encourage marrying, like not offering hdbs to single people under 35. You certainly won't see families if you don't leave the downtown area.
I'm implying two weeks isn't representative of the city as a whole. The article did a better job of it.
I stayed in a friend's apartment in an HDB and saw schools, playgrounds, and parks, which were all in use—though I'd say children were still less visible overall than in San Francisco, which is also known for having fewer children than most of the U.S.
Spoken truly like someone who never left the airport.