Every time I see a comment like this, I get the feeling that the poster doesn't understand how "the cloud" works.
Everybody knows that renting a dedicated server (or purchasing your own servers) is generally a more cost effective approach. Cloud computing is used to accomplish different goals when used appropriately.
Sure you could install MySQL on a box at Hetzner, but what happens when it goes down? Do you feel like maintaining the box for security and updates? What about log rotation? What if you need to migrate to a different geographical region, or need to increase capacity?
Smaller sites might be okay with managing those on their own, but as you grow, being able to offload that work to Amazon (who tend to know what they are doing more than the average joe) is a benefit when you have other business-logic issues to deal with.
So yes, naively getting a box at Hetzner or any other dedicated provider would be less of an upfront monetary cost, but in the long run, the advantages aren't as clear cut.
