Sure, but there's different levels of complexity, risk, cost, recovery with different services. And it depends on your design. If you do go with a NoSQL distributed DB, I would absolutely push the maintenance off to cloud hosting; that shit is a nightmare to do yourself. RDBMS you can totally do yourself, but if you're not really great at DBA/infra/etc and it's the lynchpin for your service, will you really do a better job than a dedicated cloud hosting team?