Like anything else it costs a lot to maintain a business today, whether you do your own work or have it done by others those in the business need to eat too.
The perception was that the neighbor's son should be able to mow the lawn for a few dollars, and therefore "I shouldn't have to pay much for this". The trick to this business is in cultivating the customers more than the grass.
A good landscaper over time can really enhance your lawn for a price, or you can DIY and enjoy the oudoors. I enjoy making the landscapes attractive and do it more for fun than money. Stilll gotta eat though.