It is true that the "smile" embouchure was wrong and still is wrong Bob. However it is not the worst fault a trumpet player can have. I knew an advocate of smile who while his ideas almost made my stomach turn could still blast a solid lead trumpet with good endurance. He had a High G even Maynard would have been proud of.
I expected the association of my ideas to be mistaken and attached to the smile theory when describing the fret analogy. However a stretched lip was not what i advocated. Instead the tension necessary to change pitch (in the embouchure) was indicated not in stretching the lip but in varying the aperture size through muscle and jaw movements/positioning. Wholly different from lip stretching.
The bigger fault than lip stretching (which is really irrelevant to pitch change anyway) is not allowing enough upper lip to descend below the upper teeth. We see this problem EVERYWHERE. The root of misdiagnosis in the lack of upper lip descending lies in the typical "one to two dimensional" embouchure analysis. Only a three dimensional portrait of embouchure function exposes the lack of upper lip descending.
Typically we see prescriptions of "use more upper lip" or "use more lower lip" but this is the antiquated two dimensional model view. Has no lateral context. We see only the amount of lip that may actually "reside" within the mouthpiece. Leaving blank the formula of what lip tissue is blown through the teeth and so on. This is however almost an over advanced concept for beginners. The reason "just tongue and BLOW" is the more effective approach.
I've personally so far seen only one case where a beginner needed to know the concept of lateral embouchure function in order to start a decent blow.
Where the three dimension function of knowledge comes in handy is (usually) when the trumpet cat decides to develop into a a serious lead player. Even then he may only need to switch to better equipment like the shallower pieces. Then again sometimes no. He needs to know the lateral function or progress is stymied.