Some may quibble about the definition of an engineer in that context. Stanley Hooker didn't spend his life building or maintaining aeroplanes, he spent his life designing them.
There arguably two different cultures in aeronautical engineering. There are those who think that all the work is in designing, testing and building the aeroplane, and then once it leaves the factory - all the work is done. And then there are those who think that aeroplanes magic themselves into existence, and then all the work starts. Both are, of course, completely wrong.
On the subject of involving yourself in your aircraft's maintenance - in my experience it can save a great deal of money, so long as you have taken the trouble to understand the issues properly.
I have a CofA aeroplane I lease to a flying school, and get maintained by a shop who are very competent, but are much more interested in getting the aeroplane out the door fast (good) than in keeping the bills down for me as the owner (less good). By challenging them on regulatory necessities, being prepared to go searching for serviceable second hand parts myself, and so-on, I can generally shave about a third off what the bills would be otherwise.
It's frustrating having to do this - but in my case at least, as they do everything else fully to my satisfaction, for the moment it's worth the trouble.
G