Well then, what you need is the context:

The context being that most professional pilots are not practicing
engineers? Obviously. Engineering is generally project based, and
thus not something that can easily be done part time. Can't put the
project on hold while you fly a five-day to Norita.

We also have airline pilots who are MD's, dentists, lawyers, etc., etc.
but that sounds an awfully lot like work.

Actually, you don't. What you have is a lot of MD's, dentists,
lawyers, etc., etc., who are also airline pilots. There's a
difference. I know lots of MD's, JD's, PhD's and such who pick up an
ATP certificate in their spare time, just for the hell of it, even
though they generally don't have anything like the spare time an
airline pilot has. I have yet to meet an airline pilot who has ever
picked up an MD, JD, PhD, or even a BE in his copious spare time. The
level of achievement involved is dramatically different.

I do know several airline pilots who started out in engineering school.
Not all flunked out of engineering and had to change majors - one I
know actually managed to graduate with a C average. He's a captain at
the majors now, twenty years seniority, driving a Boeing around,
figuring out how to live on less than an engineer a dedade his junior
makes and what to do about his retirement, and wishing he'd developed
some actual skills. I suppose with legacy carriers all going bankrupt
as the low cost operators eat their lunch, there's a lot of that going
around.

That's not to say that none of the A students in engineering become
professional pilots. Some do. You find them in flight test, the
astronaut program, etc. Airlines? Not so much, though every once in a
while you will see one doing it as a retirement gig or a diversion from
his consulting business.

Recreational flying is not in the same league.

Recreational flying is what you make it. Of course a pilot with 100
hours can't be in the same league as one with 10,000, but in my
experience, a recreational pilot is generally a better pilot than an
airline pilot with the same number of hours. Maybe it's because you
can't swing a dead cat at the airport without hitting a few engineers.

Michael