I don't have statistics on how big cloud computing is projected to be in the upcoming years, but Amazon is clearly poised to take advantage of this huge, relatively new market. I could see their P/E reflecting (at least to some extent) their unique ability to capitalize on this.
But how big can it be? Almost by definition dedicated servers are always going to be cheaper. Any business that needs a dedicated server is going to get one, with lower/flexing demands sure, they'll go with cloud. I love AWS as much as anyone, but there's plenty of competition out there and I now use Linode.
Economies of scale create a cheaper alternate solution. That was accomplished in physical goods years ago and the cost of "transporting" physical goods is much higher than the cost of "transporting" massive data processing power.
It's easy enough to produce compute units at a lower cost than amazon. I'm doing so even now... and you can bet your bottom dollar than amazon is going to lower their prices more slowly than costs fall.
But that's why amazon is in such a strong position right now. They are basically positioned to become "the oracle of cloud computing" - Who cares if it's slightly more expensive... if you are a middle manager in a large corporation, paying another 50% or even a few hundred percent more is no big deal if it greatly decreases the chance of a big meltdown. And more to the point, if it protects you from blame when there is a meltdown.
edit:
This is what I hope will happen, anyhow, because if amazon wanted to scrap with me down at the bottom, you are right about those economies of scale. they could crush me like a bug.
But I don't think they will. I think they prefer to just take their efficiencies as profit, and target the larger customers who are willing to pay extra for the comfort of a big name
