Everybody should stop hating on the CIM course. We all know CIM runs faster than NYC or Boston; that's why we chose CIM over those courses to run our OTQs. CIM probably runs faster than a totally flat course all other factors being equal, but only if you're prepared for the hills (up and down). A large portion of the downhill is miles 1 and 4 and if you run just a bit too fast you'll pay for it later. However it's not be much CIM has about 700 feet descent and 350 feet climbing. Since you lose twice as much time climbing as you gain descending it should be about a wash.
The major factors why so many got OTQs were that it was a deep field to begin with and the weather was perfect. The temps were cool but not cold and wind was almost non-existant (but there was no tailwind; check the weather history). Further we ran in packs and took turns sharing the lead so most had a significant draft most of the way (much like Monza).
The Vaporflys weren't a big deal. Only a handful of the OTQers were actually in them.
We should the celebrate the newfound depth and hope it translates to faster times in the next few years. It's going to be a lot easier to develop a bunch of 2:10 guys when we have hundreds of sub-2:19 guys to choose from. I think we need more guys fresh out of college running big miles and seriously training for the marathon (most of the top CIM runners were late 20s and 30s).
I think we would have had nearly as many OTQs if we were on a flat course like Chicago. Many guys I talked with aftwerwards said they had not trained for the downhills and it took a lot out of them. People underestimate the benefits of running in a big pack and ideal temperatures for running fast outliers. So yes, the course was fast and CIM may be an outlier this year, but the real reason it was an outlier was because of the competition and 40 degree dry weather.
Congrats to all who ran PRs and got OTQs. I'll be claiming my time as a PR but I do think I'll run faster someday.