Again, you are missing my point.
I said they run on 'classic architectures' ie: multi tier / layer architectures, tried and tested which, yes, in many cases include load balanced HA / failover / replication and shared storage. The kit doing the job is irrelevant, as long as it can achieve the desired goals. If you can deliver persistent sharable, scalable, highly flexible, low latency, high performance storage from a SAN or a cluster of boxes with local disk or a combination of any of the above - does the customer actually care, as long as they get what they perceive to be 'benefits of the cloud' in terms of those features?
I am genuinely not trying to argue, simply make the point that there is no one 'cloud recipe' or one best way to achieve any result.
The cloud simply offers a much lower barrier to entry to the kind of complex and high end infrastructures previous accessible only to those with big budgets.