This has just one tiny error in it - engineers ARE scientists. A scientific theory is not different at all to building something that works as intended. The same kind of paperwork, the same meetings, the same work. Engineers are not tinkerers, who throw parts into a large bucket and stir it until something useful comes out of it. Changing your engineering is just like changing a part of a theory - when you do it, you better know why you do it, because otherwise you have not advanced at all and when your machine/theory breaks, you will start from zero.
(A scientific theory could of course also be seen as a machine that produces predictions out of input data, assistants and coffee)