The girl who wrote to me the other day about sterilisation being too successful said that she was sure the town council had not trapped the cats because she could not imagine anyone complaining. Let me assure you, I hear this all the time - people cannot imagine their neighbours complaining, because usually THEY don't see a problem, but often their neighbours do.
Some neighbours will also claim that everything is fine, but complain when you're not looking.
This girl said that as no new kittens were being born, she was quite sure they were going to go extinct as she did not see as many cats now as ten years ago when they were all over her estate. There is not a country in the world where the cats went 'extinct' - the only place that managed their population is Jersey, a tiny island, many times smaller than Singapore. And of course they just stopped sterilising once the population was managed. It's not irreversible. If we ever went the way of Jersey, which I highly, highly doubt - the place is unique due to size and geography - we could always take some cats from somewhere else which is what Jersey is doing now.
On the other hand, death is irreversible for all those cats killed because of complaints of overpopulation. Why would we stop sterilising NOW because eventually there might not be cats and allow 35 cats a day to keep dying? The chances of having no more cats in Singapore due to sterilisation are so remote, I'm more likely to win $30M in a lottery first.