This statement is not accurate at all unless you are talking about consumer lenses. There are prime lenses that received lower scores based on what lensrental have posted before and it also depends on the manufacturer. But then again, if an owner of a D800 prefers using his AIS lenses, surely there is nothing wrong with that.
I totally agree with you on this but I would like add something to it that I am sure you agree with me about Glenn...
Let's face it folks modern day lens technology is incredible. Primes are great and the zooms are great. MUCH better than the old lenses. All of the old non Ai and Ais lenses for example...my 28 is soft on dslr so is the 50. Even the 105 is but this is a good thing in that case. I would wager that not many of those old lenses will translate to the dslr world successfully. They will be lackluster at least compared to when used on a film camera.
I don't understand why a D800 user couldn't use a modern wide angle zoom and a tripod say to make just as good a landscape picture as they could with a prime. Primes are not THAT superior to zooms come on...now they used to be but not anymore...