There is very little skilled involved in actually cutting someone's grass lets be honest. To say otherwise is just bogus. It IS a low labor job.
Now running and managing a lawn care company is a completely different skill set. Solo guys perform both the labor and the business aspect and since people only see them performing the labor that is what they are associated with. However they can also be very smart businessmen and many are. Many successful lawn and or landscape companies start out as solo or 2 friends mowing lawns. Business sense and drive lead these people ahead of the pack and to the top of a well run BUSINESS.
Landscaping and hardscaping takes much more knowledge then a lawn mower however again the actual tasks are just labor and people can easily be taught the proper ways to complete certain tasks. Is takes a brain and business sense to line up the work and manage the laborers.
The managers and owners of landscaping and lawn companies (the legitimate ones at least) are run by business men and women who manage the labor force.
Anyone who can build and run a successful business should at the very least have 6 figures in theirgrasp if they so decide to work for it. Weather they want the added stress and responsibility that getting there may entail is completely up to them. Some people make 50k are 100x happier than those making 500k, it all depends on the person.