LOL!
Here is what happens. The lumber they get is bought through a broker. Universal Forest Products buys for Home Cheapo.
They order from a mill that will sell them the cheapest grade available and then broker it to Home Cheapo.
At the mill, if they havent got the best equipment, the lumber is sawn across the grain instead of the most modern method of curve sawing. Wanna see a “wigglebox” curve saw gang saw in action? Here it is.
watch the movable section follow the sweep of the cant.
https://www.youtube.com/watch?v=B2-BEk2t9aE
animation
https://www.youtube.com/watch?v=tnQKhCV5jRg
What happens is that it doesnt cut across the grain and the result is that the boards dry straight where a saw that cuts across the grain, the board dries and warps.
Thanks for the two video links. That is amazing. I had no idea that is how wood is cut with the grain these days. How do they straighten the curved boards that were cut with the grain?