Asking the courts to set aside decisions seems to be en vogue this month! Microsoft has had a long-standing relationship with the DoD (and the NSA especially) and their Azure-on-prem offering has been around for almost a decade. AWS-on-prem is still new and even if it can be pulled off flawlessly there's not the track record of managing issues without calling in AWS employees. The content on JEDI will be far more highly classified than whatever is on AWS' us-gov regions... sufficiently classified that "mere AWS employees" won't be allowed to touch the systems once they go online.

One nice "feature" of JEDI is that it's not a ten year lock-in for the Pentagon. It's certainly possible that five years in the bean counters in the five-sized puzzle palace could conclude that they made the wrong decision and pivot at that time... and that AWS will eventually be the winner even if they don't get the contract for now.