This thread is about sharpness at 100% crop. Your examples are of downscaled images that will look sharp no matter what lens.
The Ultra Primes are even more soft, but for a feature nobody is looking for an ULTRA-POPING-ELECTRONIC-SHARP look. That is why many people prefer to shoot with something that softens things out.
I own RPPs and a Scarlet, and I'ved shot with RPPs in R1s and they are too sharp most of the time. That is because I'm going for a cinematic look most of times. But if you shoot 2K crops, you start to have problems.
RPPs are great, but MPs are sharper. That is all. And this proves that the problem is not with the camera, it's a limitation of the lens.
If you shoot for stills and need a 100% crop, use MPs and you'll have a better result in sharpness and detail wise.
If you can't test it yourself, there are examples here in this forum. For example take a look here:
Quote from the thread: "Master Primes are unbelievably sharp! Damn. RPPs are second (from what I could judge) and Cookes are a tad soft."
http://www.reduser.net/forum/showthr...rime-Red-Prime
Or download the 3 dpx and look in photoshop at 100%.
http://www.cinematography.net/lens-comparisons.html