gnu, your prick comment is out of bounds.
The plumber's employer takes a large share, the plumber may still be paying off loans for his period of technical training (required, plus apprenticeship, here), equipment worth thousands of dollars and general high costs of living here.
We complain, but to maintain a family, where the cheapest house runs $250,000, etc., a good-sized income is necessary.

Cheap when compared with fees paid to professional consultants (several years ago I worked free lance, charging $800/day and was cussed roundly by others in the specialty who charged $1500/day.