I'm not so sure that any particular level of population, whether very large or much smaller, is automatically necessary for a livable community. For myself, I prefer a small community but there are great advantages of large cities such as museums and concerts or medical care. At the same time, some cities are disasters such as Mumbai and Mexico City. Then again, Paris is said to be a beautiful city. So perhaps the difference is the attitude of the people who live there and whether they care and work toward the community, large or small.
I'm generally skeptical of binary choices where the choices are all one thing or the other.