I think the terminology is confusing because what the casters actually really DO when executing long casts falls into a completely different category of casting (as defined by Al Kyte) from the definitions he ascribes to them.
Here is the first sentence verbatim what Al said about the "elbow out to the side" style:
In the “elbow-up-to-the-side” style, the forward
cast starts with your elbow positioned directly
out to your side at about shoulder level with your
casting hand directly above your elbow (Figure
Here, once again, is the picture of Steve Rajeff at the start of his forward cast.
Here is another from a different cast and from a different angle.
Both seem to me to meet, not your illustrations of the "elbow forward" style, nor Al's own definition of the start of the "elbow forward" style. They do, however, seem to meet exactly Al's definition of the start of the "elbow out to the side style".
So, when the start of a cast meets EXACTLY the start of the definition of one style, yet is considered a separate and different style which starts with a completely different elbow and upper arm placement: then there is room for confusion.
Rather than labeling Steve's style as a modified "elbow forward" style, I think that at least half of the population in general would consider it a modified "elbow to the side" style.
My point is that, while it may be nice esoterically to break down fly casting into three separate and distinct categories, something as dynamic as fly casting cannot be pigeonholed that way, and each person will develop his own multiple styles for different situations encountered while fishing - so long as he knows that there is no "one right way".
Also, everyone will hopefully develop multiple different "styles" of casting during their lifetimes and will be able to use all of them during a single day's fishing.
When it comes to teaching, I think there is a difference initially between group instruction and one on one. With groups, you have to start somewhere and I think it's pretty much universally accepted that the illustrated version of "elbow forward" is the best way to start beginning classes.
For someone like Turbine and many of the people in here, it may well not be such a great idea.
Cochise's casting in his second video, for example, would not be a good one to demonstrate for a beginner. They would see an uninterupted backcast to about the 2:45 position when in fact the backcast was completed somewhere around the 1:30 to 1:45 position. But he knows how and when to unload the rod to get the trajectory he wants and a nice tight loop. It is a very relaxed, easy, and open "style" of casting. (But that first video looks like you might have a a bit of "creep" creeping into the forward cast, when going for more distance, Cochise
As for other observations on changing styles, I've seen a marked change in the casting style of distance caster Paul Arden over the last 4 years if he is using the style in competition as that demonstrated during his Malaysian tour that can be watched on youtube if you do a search.
He has changed from "casting-side foot forward" to "casting-side foot back, and has changed his grip from thumb on top to palm forward. He also evades a question regarding the "stop" in his second video of those two I watched taken in Malaysia. I don't know what style he uses now in competitions, but I'll bet "Fluffchucker" does.
So, in short, styles are not set in stone and can be combinations of more than one. A front and back rocking overhead stroke from the bow of a Maverick skiff can set up a rocking motion so bad that the guide may need dramamine before going out. That style is not conducive to catching fish either. Conversely, a Lefty tortional style will not raise a ripple.
Just as "there is no disadvantage to being able to cast far", neither is there any disadvantage to being able to cast with a number of different "styles" or combinations of "styles"
Until that second to the last paragraph (above) I have not mentioned Lefty's style. It is the elbow "out" and the elbow "forward" semantic cluster that raises confusion.