The US government decided that sapwood wasn't a flaw, you can get a pure sapwood board and shouldn't complain. They also recently changed the standards so that a 5 foot long board is as good as the one that previously had to be 8 foot minimum. Try telling someone who wanted a nice brown piece of furniture that white is just as good. Or try building a 7 foot tall cabinet or 6 foot long table. So in my area the price of walnut (just over $4 for 4/4 under 8 inches wide) hasn't gone up much, but the quality has dropped to bordering on unusable.
There is also a saying, "When you buy a steak, you also pay for the bone" so I have never been given a break for knots, etc.
For wood as nice as yours looks, don't be too upset! If I need a really good piece I often buy from specialty shops rather than lumber yards, and pay several times as much...not the price you paid (yet), but still absurd.