Posting this without reading any of the others so maybe I'll be treading oft-repeated comments.
"where the market is headed" seems to be 'mainstream' as not just mass-drop, but ICW (I think that's the company? Where my work buys all their vaguely technical odds & ends) and other normal-people-see-them outlets list mechanical keyboards (with kailh or gateron brows but still). Even the oddity of the 87-key is not considered so odd by my coworkers (of course, I talked the boss into buying my desk a QFR)
With the M-D run of hall-effect in three different sizes, and Ellipse' run of model-F keyboards, in addition to the many Cherry clones I think that the 'enthusiast' market has grown enough to throw the kind of money needed at all the known ways of registering a key-click.
What I don't see, much to my chagrin, is much at all outside the serious enthusiasts corner of layouts that aren't ANSI-125. I want to see more vertical stagger, more two handed keyboards. Or at least ANSI-150, or better yet 3x spacebars but no,, that's still too weird for everyone. Which I guess I can understand, but maybe as keyboards like in this giveaway gain traction, those control freaks out there will begin to realize they aren't tied to "what the store sells them."
A coworker likes to point out a discussion once held in a programming class, about GUIs and other interface choices. How many of the programming students drove a stick shift car? (8/10 IIRC) What do the students think is generally more popular "out there" (close to a 50/50 split). The truth of the sales records is that automatics are, and have always been more popular.
The lesson, then, is "know your audience. ... And your audience is not [like] you."
So, where the market is going, is wherever resides the most efficacy with the least amount of thought. Given the proliferation of tablets, and people who think a laptop, or a tablet, or their wii, is a suitable replacement for playing the upgrade game (IE they don't have a computer just a phone) Bluetooth adapters are probably the next big thing.