no... lol. Far from it. The bathroom was put into half of an old tool shed. It's amazing what some tile, some brickwork and some siding can do
Honestly I know the reason why no one has outside bathrooms. It's not really cost, it's the PITA of running sewer. That's the hardest part easily. A toilet, Vanity and sink and some tile from Home Depot is well withing the budget of any middle class person, but paying someone to run a sewer line across the yard probably is not.
We did it ourselves. I rented a trencher from a local rental place, dug the trench and laid the PVC pipe myself. Tied it into the house sewer line. It was not the easiest project from a physical labor stand point, but the actual cost was not much at all. It's much like the patio stone. We did a pretty large patio stone- and paying someone to do it would have cost a fortune. Things are not out of reach if you have time and ambition in excess, even if the checkbook is small.