My perception is that the value of relievers in a trade has gone up tremendously over the last 10 years. The market is valuing them higher in trade. They are getting paid more. Good relievers are scarce. Sometimes you can roll the dice and find a good reliever off the scrap heap. That's a fine strategy during a rebuilding year, but most contenders don't want to rely on picking up Simon types to fill out important roles.. Even the Reds planned on using Simon for mopup, until he performed so well.
But yea, Walt did a brilliant job getting Hoover and Simon last year. Not so sure we can count on that every year though.