What you might think is thatch at first glance is not. The clod is ~ 8-10" deep, rooting extends well beyond that despite the compaction. Further, the area that is clearly well aggregated is a result of topsoil additions (sandy loam), core aeration (3-4 times over ~10-12 years) with annual overseed & compost topdress. This is a good example of how ineffective core aeration is at dealing with deep compaction, and why people should address these issues before planting out.
This particular area of the site is an irrigation nightmare in it's current state. This soil is prone to becoming quickly "swampy" as a result of the compacted layer, however I have never personally seen standing water in this area despite the compaction. Allowing the soil to dry too much results in browning out in the summer despite other areas on the same site (and in same area) not browning.
Just an FYI, just because something exhibits hydrophobic properties when dry does not mean it stays that way when wetted (ex. thatch).