You are right in saying you could do it full time back at home. This is something I will probably be doing for my CPL or FI ratings.
My personal experience of cancellation/flight hours per month is based on only flying at the weekends due to work pressures, the pressures of keeping a girlfriend happy and the attraction of then going to the pub with my mates
. I am sure you could get a lot more flying in than I managed if you really wanted to.
For me, California also provided lots of local attractions to visit when I wasn't flying.
Back to the original post "Cheap American PPL's A Waste Of Money?" I would say no, just different and overall not as cheap as you think they are.