The other challenge I’m seeing now is software. Fusion 360 seems like the best free non-Windows option; but setup is not trivial.
The CAM process with eg. Cura for 3D printing is easy and reliable; still getting my head around the process for milling.
I think the closer it can get to plug-and-play, the wider the audience - eg. I think it is an interesting challenge but I can see where it would get frustrating if what you want is a DIY-but-easy-and-cheap way of milling a PCB, or engraving a sign, or cutting out some 123D Make stegosauruses!
So, for those who have good settings files, perhaps it would be good to aggregate them in one place. Eg. here is the workflow and settings for engraving a sign, and here are the bits you need if using a Dremel, and here are the bits you need with a 1/4" router.
That would then open up the field to those less interested in the “fabbing” side, but who need the capabilities — robotics, radio, custom packaging, signs, branding. Something like a ZMorph or an Othermill costs >$4500 in Australia; >10x cost of MPCNC.