I have to agree.

The engineers who developed our cars know a little more, I'd hope, than we do and therefore, hopefully, know what they're talking about when recommending/requiring operating fluids.

Not to be a smart @$$ but...

Based on your "automotive engineer's" way of thinking... you might as well run store brand 10w30 oil in your car and save more money. The car would run with it but just like lower grade gas, the unseen damages taking place inside your engine will cost you a lot more down the road than paying a little more as you go.