Although no space transportation system can keep up with the number of children being born, at least space provides an option. One can either stay on Earth and live with the population control laws, or emigrate into space so that one can have their Walton clan. Now when you ask someone at a cocktail party what they do and they say they're into real estate, they may not mean sales. They might mean manufacture. The asteroid belt alone would provide the resources to build sufficient habitats to equal 3,000 times the livable surface area of the Earth.
Space habitats make the entire solar system a home for humanity.
With most industrial manufacturing activity taking place in space, the Earth's primary industry now becomes tourism. Interest then rises in restoring the natural environment to what it was before the industrial revolution. Eventually some habitats begin to drift away from our star to take up residence around other favorable stars. Now not even a super-nova could kill off the human race. Let's do it.