I can't speak to the other projects' motivations, but I know that the fact that patents were expiring made little to no difference on our decision to make a printer. If you can believe it, the Fab@Home was almost an afterthought. We had top-of-the-line commercial 3D printers in the lab, but they didn't do the kind of custom material jobs required for the project that Evan Malone was doing. His PhD project was to create a 100% printed-from-scratch robot, and no technology fit the bill. So, he and Hod built one in order to get that project done. Like the Oculus, technology had advanced to the point that doing this was actually feasible on a shoestring budget. It ended up being a project of its own, but it wasn't like they saw the patents expiring and all of a sudden decided it'd be great to open-source a 3d printer design.
With how popular 3D printers are getting nowadays, it's possible some companies are looking to take advantage of the expiration of SLS patents, but I wouldn't hold your breath for an open-source project. If someone was making one, you'd know about it already.
On the other hand, I agree that only relatively recently has this become feasible to do on a shoestring budget. So there are a number of factors involved.
Both should be completely legal, shouldn't they?
I recall a story about a guy who blogged about coding up a shazaam clone and then receiving a C&D from the patent owner. It was never settled whether he had any grounds to do so, but sending C&Ds is cheap and mostly consequence-free.
But distributing detailed plans (or source code, as mentioned in sibling comment) of something that enables others to easily recreate something covered by a patent just seems to be less clear-cut to me (IANAL).
Patents forbid you selling anything, even with no profit.
Lots of pieces need to be sold for making 3D printers accessible for all. The electronics controlling board, the hotends, the friction wheels.
Most of the general population can't fabricate those things, but they want to use 3d printing anyway, like most women(90%of reprap now is men) don't know(or care) what a fuel injector is but they want a car for going to work.
In the future it is about Inkjet cartridges, wax and ceramic binders.