Is premature scalation a real disease?

Update 3: InfoQ's Big Architecture Up Front - A Case of Premature Scalaculation? twines several different threads on the topic together into a fine noose.
Update 2: Kevin says the biggest problems he sees with startups is they need to scale their backend (no, the other one).
Update: My bad. It's hard to sell scalability so just forget it.

The premise of Startups and The Problem Of Premature Scalaculation and Don’t scale: 99.999% uptime is for Wal-Mart is that you shouldn't spend precious limited resources worrying about scaling before you've first implemented the functionality that will make you successful enough to have scaling problems in the first place. It's kind of an embodied life force model of system creation. Energy is scarce so any parasites siphoning off energy must be hunted down and destroyed so the body has its best chance of survival. Is this really how it works?

If I ever believed this I certainly don't believe it anymore. The world has changed, even since 2005.

Thanks to many books and papers on how to scale the knowledge of scaling isn't the scarce precious resource it once was. It's no longer knowledge tightly held by a cabal of experts until Nicolas Cage flies in and pries it out of their grasping dessicated fingers. Now any journeyman computerista can do a reasonable job at designing a scalable system.

Not only has knowledge dissemination improved, but so have our tools. Drastically. At one time building a scalable system up front would have required buying and configuring a truck load of servers, building out a data center, configuring a spider's web of networks, and bootstrapping an equally nasty storage network. All extremely complicated and disaster prone. Now you can use services like Amazon's EC2/S3, 3tera's grid OS, Joyent  to cut significant parts of all that complexity out of the system.

While most of us toil away in anonymity and scaling problems are just a fond dream, when the webosphere does find you it does so with a crush.  With a little thinking ahead Blue Origin was able to handle 3.5 million requests and 758 GBs in bandwidth in a single day using S3. Did that effort prevent other features from getting implemented? I seriously doubt it.  Usually doing the right thing isn't harder if you know what is the right thing to do.

And what if Blue Origin wouldn't have been able to scale? Could they have recovered from the opportunity lost of grabbing the iron when it's hot and when potential customers are interested? Ask Friendster.

What do you think? Has most of the risk associated with up front scalability design been squeezed out? Is premature scalation still something to be avoided? Or have times changed and does doing the simplest thing that could possibly work now include worrying about scaling up front?