Even though you turn the mowers off the greens generally, it may be that a bunker prevents turning there, or it prevents it somewhere else so there is more traffic because you have to turn there for more passes.
Also, green perimeters stress more because they get clean up passes every day, meaning machines run over the turf twice as much as the green middle. Add in stress if in a cart path walk up area, slight rises among green contouring, etc. and its typical for the edges to have more trouble than the middle.
As to Sub Air, I think its worthwhile, but its only a 5% improvement over nature. If you plant bent in the south on a wooded site, you may have caused more microclimate issues than you can overcome, even with sub air. I have seen greens in deep woods where the sub air may help, but not enough to overcome the shade and dead air.
I think its interesting to note that an urban course could have temps higher than other courses, even nearby. I tried to make that point to John Kavanaugh earlier this summer on his green quality thread, albiet I was talking about his course being in a bit of a hole, which can also cause differences.