Some people posting on this forum seem to be unaware that there are photographers who shoot a video every now and then, birthday parties, children and the like... and there are videomakers, plenty of them. The market is not huge, they have no reasons to use a Pentax, but they do exist
Many music videos, documentaries, shorts for the Web, etc etc, are not shot with videocameras. I personally know a few videomakers who use "still cameras".
Not necessarily micro 4/3 mirrorless cameras, I've seen APS-C and FF reflex cameras too, and as far as I know the quality is good.
The problem is not the sensor. With adequate optimization/codecs/processing power my K-1 would be a great tool to shoot at prosumer level.
Ricoh seems to dedicate it's limited R&D resources to other fronts. Not surprisingly, I'd say. There are other priorities.
Though there is a market for video optimized cameras (Panasonic caters to that market, for example).
Cheers
Paolo