I just looked at the mowers at a commercial lawn mower shop. They mostly sell to the pros. My old mower was a professional grade M series with a magnesium frame. To get into the same level of mower now they start at $600 and go up to $1299.
It is like the difference in Snap on tools compared to Craftsman. I only mow my own yard. But if I am using a tool once or twice a week for 8 or 9 months a year I want good equipment. Easy to use design and easier to maintain.