Nah, I'd say the job of practical engineering is to provide reliable, correct solutions in a timely, in-budget manner.

If you are talking about theoretical engineering, I agree :D

> the job of practical engineering is to provide reliable, correct solutions in a timely, in-budget manner

Sure. And I'm sure you'll agree this job is easier to do in direct proportion to the celerity with which we eliminate impractical approaches.

You can eliminate impractical approaches all day long. At some point you have to start with the practical approach that you know will work a-priori.

When you have the option, sure! Not all problems are so tractable.

Granted. Still, I think there is a fundamental difference: In theoretical physics, a good theory of how things work (or how they definitely don't work) is enough as the result of your work, you don't need a working product in the end. In practical engineering, you do!

Let me also add that I am serious about theoretical engineering, actually that's one of my favourite occupations, together with practical engineering.