Not wholly unreasonable...
The idea that multiple vendors would be better value (as is claimed by the AWS/Oracle teams) is, frankly, suspect (as the gov submission notes). Whether or not the admin costs of having more than one supplier are outweighed by the savings on each line item seems less important than the costs of managing twice as many security solutions (and potentially cross-domain solutions between them).
Yes, it's obviously true that no vendor is going to be immune from vulnerabilities, but it's also true that a connection between (say) Azure and AWS will provide twice as big an attack surface.
Biting the hand that feeds IT
