The easy answer is definitely "We go out, and write our own scenarios, and show 'em how it's done!"
I'm not sure anything I could produce will do anything but hurt the cause, but I'm willing to give it a couple tries some time.
Writing scenarios for general public use is definitely an art with a different skill-set than running a home-brew adventure for a known audience, though, so I think it's fair to admit that the "easy answer" isn't as simple as it sounds at first.
If it weren't for the fact that the future of the Chaosium Monographs seems to be in question right now, I would have suggested adventure contests similar to the ones used to populate the Halloween Monographs: in each of the Halloween Monographs I've seen so far, there have been two or maybe even three scenarios with some refreshingly unusual settings, so I know there are writers out there who are interested in thinking outside the 1920s Lovecraft Country and Delta-Green Modern boxes, and that the monograph contests offered them the opportunities to do so.
I think the Wiki offers some opportunities: as I've been filling out entries in the Wiki, whenever I notice a scenario that lends itself well to being relocated to an offbeat setting, I leave a note (one or two sentences) about the opportunity in the "keeper's notes" area. Keepers aren't necessarily going to see or use those notes, but if it helps just one person to see the possibilities....
I think the forums offer a LOT of potential: if I were to ask for help with something specific, I'm pretty sure that in no time there'd be replies from people loaded with the unique experience, advice, talent and creativity of the forum members here. If you were to produce the skeleton of an adventure and ask in the forums where and when to set it, you'd almost certainly have a half-dozen suggestions you never thought of within 24 hours. If you have an unusual setting and a general plot, and ask in the forums what to use for a villain, monster, deity, tome, or artifact that would fit the plot and setting, you're bound to get plenty of weird and creative suggestions, as well as some more traditional suggestions adjusted in creative ways to the weird context of a unique setting. Perhaps the folks in the forums would be interested in some monthly threads containing a set of prompts of this sort which would, effectively, result in some unique scenarios produced as a collaboration from the YSDC community... just add an editor to put the whole thing together afterwards (the really tricky part!)....