I think a lot of the fluted points were designed to be as thick and strong as possible, but still have a thin hafting area. You can't get a base on a thick point that thin that far up by pressure flaking. There were a lot of fluted point types, including Clovis, Folsom, Crowfield, Cumberland, Redstone, and a few others that were almost always fluted. Also, many Daltons, Hardaways, Simpsons, and other transitional Paleo points were sometimes fluted but not always.