'Sometimes have a usable product' ... have you tried the K-3? Better image quality than the crop Canons, far more user-friendly than the Nikons, and much better value than either. (The only aspect I've so far noticed where it lags behind Canikon is the autofocus performance. But unless you're shooting sports or moving wildlife, the AF is perfectly adequate.)
I didn't have a ton of K-mount lenses, but thought it was worth eBaying all my Canon gear to switch across to Pentax. No regrets.
Why on earth do you think they'll 'not survive the decade' when they're innovating, and when their share of the 'interchangeable lens camera' market share hasn't changed (during a period when Canikon's market share has gone down significantly)
You get roughly same IQ on Pentax that you get on Nikon because both using Sony sensors.
I was under the impression that top of the line Pentax has a good AF system, I am surprised there.
Why Pentax might disappear in a decade ?
Well I think same reason that Canon and Nikon face, I think mirrorless is the future whether we like it or not and while Nikon and Canon probably have the financial resources to R&D into mirrorless if they want I don't know if Pentax does.
I do hope they will, Pentax makes great cameras, not for everybody but they are good, I hope to see them in business many years down the road but I guess we will know that in few years from now.