There's a wonderful podcast, Shannon's Lumber Industry update that discusses this topic in detail, I can't track down exactly which episode. The point he makes is, yes, sure they are "better" lumber, but lumber can also be a sustainable resource. We've done a MUCH better job producing construction lumber (what those two-by material is used for in the vast majority of cases) in a sustainable manner. That old framing lumber came from just demolishing old growth trees. You can still find comparable lumber, this is what fine furniture makers do.