Another point to mention is that you don’t have to go through all those steps as most of the existing web site did today as there are new framework that comes with caching and the ability to execute async requests in parallel in a much simplified way.

You can read one of the examples below:
http://blog.gigaspaces.com/2008/08/07/scaling-out-web-application/

The architectural points you record are good ones. What I’ve found is that these are enablers. You still need excellent system administration (just as you need excellent developers) to take advantage of them. In many real systems, developers code around their system adminstrators, because the ops team literally can’t implement the architecture. For example: I once worked in a group which takes weeks to stand up a new machine after the hardware is received, or to simply add a queue to a cluster of existing queues. The code contained all kinds of hacks to keep from having to add a new queue as a result; architecture out the window.

The obverse is also true: sys admins often have to tune around the limitations of their developers. I’ve seen Java teams spend literally months trying to resolve memory usage issues with tuning instead of just fixing the code.

Teams generally are limited by the people they have. It’s a rare group who is free to hire and fire at will–thereby acquiring the talent they need to implement a given architecture.