Going out on a limb here with just a couple of thoughts…
1) "They don't make them like they used to". An old adage, but I've noticed waviness in new car windows that I never saw before. I'd offer on this one, that the quality of yesterday, isn't the quality of today--and as there are only a small handful of windshield manufacturers, we are beholden to what is available.
2) "Florida Heat". I have no doubt from what Bill describes as the beginning of some de-lamination in the corners. A windscreen is made of two layers of glass (inner and outer) with a polyvinyl plastic bonded in-between. When it starts to de-laminate, you get a waviness around the edges, and I bet that's what Bill describes. I bet the heat and sun of Florida might be a contributor to this issue, but that's only a guess.