We got a huge percentage of humans who are struggling. Many under educated. We got slavery. We got wars. We got food issues.
I’m not convinced that these problems would be addressed by a smaller population. On average, people today are better educated, more peaceful, and better nourished than they were 100 or 500 years ago. I think this is mainly due to technological progress rather than population size.
I think asking why population needs to continue to rise?
I don’t think the population needs to rise, but there will definitely be problems if the population shrinks rapidly over just a few generations, one of the main ones being “who will take care of all the old people?”. Japan and Korea are already struggling with this, and other countries are not far behind.