What motivates you to say that? The term "cloud" itself is not that old. I understand some of the tech underlying was already here 10 years ago, but the combination of these to what we call the cloud wasn't - it's even still being built.
I'm not the parent, but let me shed some light on that.
I've been using Amazon's services ... EC2, S3 and RDS, and now trying out the Elastic MapReduce.
These services simply rock my world, and the prices are competitive enough that third-parties started building and selling their own infrastructure on top of Amazon's services ... like Heroku, MongoHQ, AppCloud or Stax. And all of them have brainless deployment and competitive prices.
Short story ... Amazon's services are awesome, and both Google and Microsoft are late in the game. The only way they could beat it is through better prices, but other than giving away monthly freebies I'm not sure how they could do that.
One way to beat Amazon is to make cloud development easier. I think they will do that. IMHO, Microsoft does make good development environments. People will pay for ease of use.
Another way is for Microsoft to do a great job of selling the cloud to its enormous client and developer base. I think they can do that. I suspect, but don't know, that most corporations would be happier with Microsoft behind their cloud than Amazon. A lot of corporations will have 10+ year relationships with Microsoft and/or its resellers, certified developers, etc. Amazon to them is an online store.