This is my husband the civil engineer's pet peeve. Most builders, developers et. all, after they get through with the dozers and earth moving do not compact the site enough (if at all). We saw houses being built in Atlanta on slab with no site compaction. They had such severe settling that the roofs were affected.
They may compact the area under the street but not the area under the pad. And neither is compacted to make my husband happy I suspect, as he use to work on state highway construction and tends to want to over-engineer everything. That said in this case he is most likely correct. If the area where the slab is to be poured is compacted, heavy watered, compacted again with multiple repeats, hubby says there wouldn’t be anywhere near the settlement that you see in most new construction.
Most of us who lived our lives in houses built on foundations instead of slab; don’t realize the site should be compacted.
As you all seem happy with your houses in TV, some compaction is probably being done, maybe the week some houses were built they were sloppy?