I think engineering for 'The Cloud' can be just as time consuming if not more so for start-ups. For Amazon at least you have to engineer for failure. With a dedicated server configuration you still do need to engineer for that, but you aren't worrying about if depending on the solution providers block storage is going to take certain aspects of your architecture offline when it goes down (yet again), or if the portal won't allow you to bring up/down new instances during a very critical period of time, etc.