That's not the only issue; there's also a lot of compliance issues that having a hosting company can take care of. There's whole sections of PCI and HIPPA compliance that you can just write off as "not our problem, talk to AWS".
Theoretically, it isn't. In actuality, and in our experience, there are a lot of compliance standards where just saying "we're on AWS" gets you 90% of the way toward acceptance. Its mostly buzzword compliance.
That's just not true. Most of PCI compliance is documenting practices and operations. Have you even completed all various levels of compliance? Or have you just done one level?