The kiln drying process is exactly why you get what you get. When you crank the kiln to 11 in order to get the most throughput out of it you get residual stres

The kiln drying process is exactly why you get what you get. When you crank the kiln to 11 in order to get the most throughput out of it you get residual stress and bent boards. A covered pile outdoors or in a warehouse will yield straighter lumber (or just don't crank the kiln to 11) but that is not economically viable for random pine that people frame things with.