that's where the market was at and they could get it.
It was a good lesson for them to learn that you can make a lot more money by taking initiative to find a service in demand rather than just taking whatever job you find.
There's a lot more that goes into than just cutting grass and trimming. My boys had a full load of clients which meant that they had to line up back ups for when they were out of town. Also, it's challenging to cut 15 lawns per week once school is back in session. They spent virtually every evening and several hours on Saturdays servicing their clients.
No way would they have gone through the trouble of all that for $15 per lawn.