The money is not only in the infrastructure
It might be true that AWS, Azure, Google, IBM Bluemix are hard to beat on infrastructure. This does not mean it is impossible. For example Digitalocean is trying and has some success.
There are also a myriad of smaller players which offer great value for money or localized services.
But the real money is in ease of use. Most developers don't want to struggle with infrastructure and scaling and administration. They want a CLI wich offers a single command to deploy applications. The likes of Nodejitsu and heroku are the front end to the cloud servers of AWS and others. They hedge their bets by being able to deploy to all the clouds and if one gets more expensive, it might be shunned by users.
It would be interesting to know what part of revenue for the cloud providers comes from those Platform providers, from big enterprises and then from small companies.