Correspondingly, you need far fewer engineers in your company to build and maintain custom software for such things. I am wondering whether in medium term - say the next 4 to 5 years - we are going to see an order of magnitude decrease in the number of jobs in this sector.
I don't think we need less people, I think we need people to work differently. Also, an application needing of X amount of infrastructure persons will now need less than that, which frees resources to deploy more applications.
In a nutshell, I don't think we're going to lose jobs at all. I think the cloud is a fundamental pillar of the startup system, which is creating so many jobs that didn't exist before. Efficiency doesn't drive us to less jobs - it drives us to more jobs.
Once the applications grow big, the need for infrastructure people comes back. The difference is now these people are not touching hardware but software.