I appreciated the data points about homebrew adoption in "Mr. Glass goes to Washington" (Zymurgy, Jan/Feb 2016, pp. 9 - 11).
First, I wonder if the perception by potential "recruits" that homebrewing is complex is completely addressed by the extract/all-grain argument. All-grain makes a brewing session much longer, but so does the scale of the typical 5-gallon brew. Brewing at half that scale gets around issues that made 5-gallon batches more complex for me: the need to brew outside the kitchen, and the equipment required to do that; the equipment required to chill a 5-gallon batch down to fermentation temps and then maintain it there throughout the process; storage issues; very long bottling sessions; and the stakes of brewing a large batch that could turn out bad or at least disappointing. There is also all the lifting/moving of over 40 pounds of liquid in large, heavy containers, longer cleanup, etc. AHA even has an article on the website making the case for smaller brews: http://www.homebrewersassociation.org/how-to-brew/a-big-idea-on-small-batch-brewing/
However, once a brewer decides to go to smaller batches, extract OR all-grain, that means customizing recipes--easy enough to do, with a little experience, but a step up from the kit brews. I'd be curious to know if the homebrew stores that sell one-gallon starter kits see higher hobby adoption by those customers, and what those customers do next (AG, BIAB, etc.). I would also be curious if some customers buying Northern Brewer's 3-gallon BIAB kits are simply doing smaller AG batches with existing equipment.
That said, if encouraging extract brewing by existing homebrewers becomes part of the AHA membership recruitment strategy, why not make extract recipes more prominent in Zymurgy, or establish a "Busy brewer" regular feature, and/or a small (even informal) competition? Or side-by-side recipes, with taste tests? (And for that matter, time tests.) Could the "Commercial Calibration" crew taste the difference between extract and all-grain brews of the same recipe?
Anyway, thanks for good food for thought.