agreed, but it depends on how hard you wear them. Thighs on my NC were painted on when new back in late June. I listed them on B&S, but when they didn't sell, I figured WTH, squeezed into them, and decided to experiment with how much they'd stretch.
Since then I wear them 5 or more days a week - airing out every night - and whenever possible engage in physical stuff like helping friends move, lots of walking, etc. They have stretched at least 0.5-.75 inches to a snug, but comfortable wear (my personal preference with denim). YMMV, but a commitment to an initial few months of discomfort and regular wear will get some thigh and knee stretch, but obviously not to the extent of waist stretching.