Canon and Sony were always going to come crash the party Red created. It was a matter of time. Canon came in first because they have no upper end video to protect. Plus having 4k is part of the bigger picture with Sony and their 4k TV. So they will jump in big next year.
I agree it's getting crowded and that's only good for the buyers. 4k is the new HD variance so we'll see how the market unfolds. Scarlet and the 1DC are similar except Scarlet is upgradeable to the Dragon sensor, one of the big things about Red. But then again Canon/Sony will have the workhorse reliability vs the overheating batteries/beta software of Red.
Red will always have a following because of the ability to upgrade sensors, something the big boys won't do in their design because they need the volume.
Dragon sensor upgrade 6K res. for 6K spondoolies
120 fps @5K