IT DOESN’T MATTER! It’s not about one plumber. It’s about how much a plumbing firm with a handful of employees can earn, and how much the owner will have to take out to service the debt he’ll have to take on in order to buy the business.
In the “trades” they are known as “$#!T Directors” and do quite well.
With the exception of Electricians, they are probably the highest paid contractors when it comes to new residential and commercial buildings.
You’re right. And what self-respecting plumber doesn’t have a few plumber’s helpers, anyway? ;-)