Well, companies are jumping at the chance to put themselves at the mercy of other companies. Basically another form of outsourcing. Except when the internet goes out you lose access to all your stuff. So I imagine that will be a decent career path. However, the cloud companies need all the same old roles, not just people certified in a specific product stack. Nothing wrong with having it though.
From a personnel point of view it makes a lot of sense. Why have a trained support team at every company when you can pay one company to handle many at once. It concentrates experience and as long as the problems don't exceed capacity everything should be fine. It simplifies disaster recovery and security by saying it is someone else's problem. I don't think it has been around long enough as a concept for the long term problems to surface though. Just waiting for the first one to have a major problem. AWS had a major outage a few months back, but recovered.
Not to say that externally hosted and supported solutions haven't existed for a long time, but on a smaller scale. Except for maybe payroll and e-mail.