To get back to the thread's original question (though I do love a good debate about the definition of a word like "incremental"), the answer is no.
The 7:17 is not more impressive than a sub-2 hour marathon. The sub-2 would be more impressive than the 3 second improvement in the 3000m.
With the super fast tracks, the bi-carb, the super shoes, the double thresholds, etc. I think that taking 1 second per Km off of Komen's record is "doable" for a super athlete like Jakob. I know it is doable because Jakob did it.
Going sub-2 in the Marathon was widely considered humanly impossible and when it happens, it should be rightly considered the most amazing result in our sport.
There is just so much that can go wrong in a marathon and you only get a couple shots per year. You might only get a half-dozen shots at the race while at your peak. That alone makes a "perfect marathon" harder to achieve.