Different tools for different jobs. I have 1/4", 3/8", and 1/2" drive ratchet in my toolbox even though I can get fair amount of overlap in the sized of sockets I can get for each of them.
The 6.5 Creedmoor was originally designed to be a PRS/Practical/Tactical style match cartridge with an optimized case design that addressed some of the inefficiencies in the design of the 260 Remington; namely a shorter body with less taper, steeper shoulder, longer neck all in an effort to make a very effective flat shooting low recoil cartridge that could seat long/heavy for caliber high BC 6.5mm bullets in a magazine fed short action. Along the way, people found out that coincidentally all of these features also made it an outstanding hunting round for medium sized game at intermediate ranges.
The 6.5 PRC is a different animal entirely. It shares some of the same characteristics of its little brother, but I would argue its primary role is to serve as a intermediate to long range hunting round. Case size and resulting mag capacity as well as additional recoil and decreased barrel life effectively rule it out for PRS/Practical style match shooting. Those competitions are dominated by the small 6 and 6.5mm rounds (all 308 win case derivatives).
With that in mind, I doubt the timing of the two introductions makes either one of them obsolete, or will drive any mass switchover to from one to the other. As others have noted, the advantages of factory support from Hornady and the aggressive marketing and support gives them all the staying power they need.
For me? I hunt (sometimes at ranges that would be considered "long range") and I shoot PRS matches pretty regularly, so I own a 6.5 Creedmoor that is geared towards match shooting. I also handload and with 143gr ELD-X my current setup carries >1000 ft lbs of energy out past 800yds even assuming very low density altitude, so yes, I may get a PRC at some point, but it would be a very hunting biased setup.