: Middle-earth was a mixture of peoples and cultures, and Tolkien used more than one model to create his world. He also freely intermixed elements from different times and regions.

When you folks speak "Middle-Ages" and Michael calls them "crowded" you seem to forget that the period we call Middle Age was actually at least three ages spanning very close to a thousand years. There were times when you could not exactly call them crowded. As for example the 5th- 10th centuries or the period of the Black death(s) and warfare in the 14th century.
Depending on time and place, Western Europe could seem crowded (if compared to earlier periods and not round the Mediterrenean) on occasion, but it could also be a very desolate or depopulated place.
NT