I think it is pretty simple, Hoya knew they needed a mirrorless for K mount, they knew they needed to be different since they wouldn't have the small size so they went hunting, meanwhile a lot of tech was being developed for the KR replacement (long overdue now) so they put it together. Low cost (aside from designer fees) as everything in the camera was likely already being developed for the new prime engine. It opened up a new market with out them investing a lot (in fact aside from the design they invested nothing since they knew the company was sold they left it for ricoh to market)
It's a funky camera, not for everyone definitely but it does seem to have a niches being carved out (to bad about a couple of the video limitations or it could be very popular)
Like the Q I think it's taking time to find it's market, but it does appear to be having some success (except of course with the people who wanted another Sony but with the Pentax name on it - personally i'm glad they didn't take the me too road, it would have got very little press, the K-01 OTOH has gotten loads of press both good and bad, more importantly it seems to have gotten traction in markets most of us have no connection to. In other words it's not an enthusiast MILC - that one of course will come later there being more critical things to get out first like oh say a DSLR line