Since you are a structural engineer you understand strength of materials, normal modes, static and dynamic loading and all that, but try to explain it to the aesthetacist that builds around human requirements of form and function. Telling Frank that he might need a brace across that nice south facing window might cramp his style.
I agree with you- the low rise, flat roof style that FLW inspired was a bad idea. The fellow who wrote the above must like wet buildings.
When I was a math graduate student in the early 1970's we used to see a lot of aspiring architects flunk out of the engineering calculus sequence (mostly taught by senior faculty, but with lots of grad students to staff the recitation sections and grade the exams). About the only more innumerate population of students in the introductory math courses were the arrogant loud mouths from the School of Journalism: invincibly ignorant.
Maybe we didn't flunk enough of them, but at least some artsy types who couldn't calculate a stress load got filtered out by this requirement.
I agree that FLW is vastly over-rated as an architect. I had the misfortune to take a tour of one of his 'Prarie Homes' one evening during a period of warmish weather. The house was stuffy, the furniture awkward, uncomfortable and impossible to move. As an engineer, it always puzzled me how he (along with Mies and countless others) could be labeled as great architects when they violated basic engineering principles, structurally unsound, and totally unliveable.