2k, 4k, 6k, I guess 8,10,12k is coming. We'll all talk about this until our heads spin and this so mirrors the medium format dslr conversation that went on for a decade in still photography.
Red is the medium format camera of the motion world, Sony, Canon, JVC all at 4k are the dslr equivalents.
Just like in medium format, RED has some more work to do in stability, usability, speed, etc., before they'll be as easy to use as their lower costs 4k competition, but that's the way this industry goes.
I do know this . . . if you going to even think about cutting in 4k to 6k, you'd better start looking at those HP peecees with a trillion drives, a million gigs of ram and video cards that could power HBO coast to coast.
Today, we shot lifestyle, tomorrow dialog. For today I used the Sony 2k fs100, looks great, autofocus, shoots fast, throws backgrounds medium soft . . . works. Shot about the same amount with the Scarlet at 4k, looks good, throws backgrounds medium soft, allows us to do some more adjustments in post that the Sony (not a lot but some) and takes more care and is more difficult to use as you have to manual focus, you have to deal with the fact the Scarlet doesn't let you play back and sound sample in camera (you can sound sample while shooting, not just playback) and of course the focus is critical to get it right, especially if your hand holding.
Like medium format stills the Scarlet, R1 and Epic are much better with some solid support, where the sony is an easier camera to hand hold, but hey, that's the price you pay for a raw file 4k camera. Now 6k, ok RED one upped them all.
I don't blame RED, hell I respect the heck out of them and like their product, though like the original Canon 1ds I like the R1 better than the Scarlet, I'm sure would like it even better than the Epic, but that's just me.
Anyway, we've seen this story before and though 99.9% of everything shot with a 6k camera is going to play on the web, there still will be a large market for it . . . I guess.
Time will tell, but if I was Sony and Canon, I'd be on Adobe's doorstep, cash in hand asking them to come out with a lightroom style color grading suite that actually worked fast and accurate.
If I was in the equipment making business, I think I'd find a way to make 800 watt hmi's by the thousands for thousands less.