"All of our problems boil down in the end to overpopulation."
No they don't.
The benefits system and the NHS are being hit by two primary problems and neither are related to over population.
The first is that people are living longer into retirement. In the 1950s the average lifespan for a man was about 65. So on average most men would be lucky to make it to retirement at 65 and then wouldn't be retired for very long. Now days the expectancy has gone up to about 77. So suddenly, on average, men are claiming out of the system for 12 years when they would have hardly made any claim at all when the system was put in place. So that's 12 years of claiming and healthcare compared to, on average, none when it was all worked out.
So we've got an increasing population who retire and claim benefits and require healthcare. And who pays for them? The younger working population, and here lies problem number 2. There's less young people.
It used to be the case that each generation was supported by a more numerous younger population. Your typical age population pyramid. Not any more. We're just on the cusp of hitting the point when things turn around, the generation about to retire will be supported by a less numerous younger population. And both these problems link together, this smaller younger generation will not only be supporting a more numerous "just retired" generation but also the older generations who are still around due to improvements in life span.
And that's the problem.
We need more young working people to pay for the current system, so we actually need population growth.
Or we need to have a sit down with ourselves and have a very serious chat about how we're going to pay for all of this because the current system is broken and is going to get much much worse as the population becomes increasingly aged and are no longer economically productive.