This is great insight that I haven't considered. IN parts of the US you can plainly see miles of monoculture forests in all directions thriving (in an industrial sense) because they are actively managed. Look around Panama City, FL, (link below) for a good example.
The western half of the US has many monoculture forests where forestry companies manage them with thinning, herbicides and selective planting.
Natural forests in the west are diverse and contain many species of trees. They are different trees than you see in the east, and many of the coniferous species appear similar.