Board Thread:Questions and Answers/@comment-1781513-20170701232804/@comment-155600-20171107003137

That's part of the reason the Replicators were invented. After Thor's Chariot aired, the question was raised as to why the Asgard didn't just wipe out the Goa'uld with their clearly superior tech, so they needed some reason why the Asgard hadn't gotten around to it yet.