It all depends on the size of the property, I picked up 4 lawns this year with my 36" Toro because the previous season a large company used their 52's and 60's to make a few passes. In that smaller area they were causing ruts and turfing in the corners, all 4 lawns were different established companies. I could have used a 52" and gone slower than my 36", but their isn't much time saving(5 mins per lawn). With that extra time I spent my 36" gave them a nicer cut and it looks better having 9 passes with a 36" than 4-5 passes with a 52". And yes, you can say that a 36" is specializing, its specializing in cut quality over production, by about a lawn a day. I'd rather keep my customers and spend a few more minutes on their lawn and talk to them for a couple mins if their home.
There is an Old Blue Chair for each and every one of us, we just have to find it.
2006 GMC Sierra 2500hd crew cab
BOSS 8'2" Power V
Hustler X-one 60"
Toro Proline 36" wb w/t-bar controls
JS46 22" walk-behind (wouldn't recommend)
Shindaiwa T254, Echo trimmers, chainsaws, pole hedge trimmer, pole saw, hedge trimmer
Shindaiwa 633 and Husqvarna 130BT blower