Is Middle-earth a place, or a time.

How can a place exist for thousands of years and not advance technologically. From what I've learned, this world has been pretty much the same from the beginning, all the way to the 4th age. I know I'm just nit-picking, but it does make me curious if Tolkien ever considered that type of advancement.

The more I delve into this world, the more interesting it becomes. The content is vast. They should remove Shakespeare from schools and teach Tolkien instead.