Exactly how do those bulk roasted beans go bad after a week? The stuff you buy at Costco is bulk roasted and then sealed in oxygen free packaging. They displace all the oxygen with nitrogen - and without oxygen, exactly how are they going to go bad? It's not like bacteria is a factor.
Fun fact for the day - did you know that many of the apples you see at the supermarket were picked well over a year ago? They seal them up in an oxygen free environment and they keep just fine for up to 2 years or so.