I honestly think that a lot of stuff sells just because the right person came along at the right time. Maybe nobody was looking for .300 Win Mag during the time that ad ran. Who knows? I've noticed that some of the commercial vendors on Gun Broker will run a specific item for a time, and then let that auction expire. After a time (30 days or whatever) they will relist it until it eventually sells.
Like others have said, I use and will continue to use PPU brass with complete satisfaction.