It's the law of supply and demand. If no one buys at those prices, eventually they lower prices or go out of business. High demand means they can get high prices. I'm not that desperate. I went into a LGS a few weeks back. They had a few 1lb rifle powders in stock for $35-40. I haven't been back.
If you are willing to wait, you can get better prices. I got lucky and caught Brownells with Unique in stock two weeks ago and bought some for $19/lb. It must have gone really fast. I ordered 5 lbs, but they are only shipping 3. The other powders I bought were $24 and $25/lb. Winchester primers were $30/K. Most on-line places let you sign up for e-mails telling you when an out-of-stock item arrives.