Another of my readers claims that overpopulation is a major world problem. The world currently has 6.6 billion humans.
Certainly, fewer resources would be used with a smaller population, but we are not currently at capacity. China alone has 1.3 billion people, and India alone has 1.1 billion. This together is 1/3rd of the world's population, all crammed into a small area. Neither one has a problem with famine at the moment. Neither food nor space is rare on the earth, at least for the moment.
However, India is rapidly growing, and China is growing despite government policies designed to reduce the population. When food and/or space runs out, it won't be pretty. In the United States, where I live, the population was 281 million when the government last counted, 8 years ago. It has increased to 300 million. Not purely by immigration.
This is why we must master space elevator technology. With a working space elevator, the wealthier humans can depart the planet to use the resources of other planets. (Which would, once they terraformed them, be cheaper than earthly ones due to lower demand.) Likely, they will wire some of this back to their earthbound families until they, too, can leave if they wish. The total human population would grow while the population that actually lives on earth would shrink. Soon, the only humans to live on earth would be those with specific attachments to specific regions. I estimate this to be about 200 million people.
Perhaps living on earth would have a special prestige in this new society and would be more expensive. Or perhaps living on earth itself would be a backwater thing to do, and spacebound humans would mock the terrestrial.
The universe as it stands now seems to be mostly empty at the moment, but it need not remain that way.