Why Building your Own Iaas why not public?

Hello, everyone. I am new to the opennebula and I am really overwhelmed with is capabilities and recently I was just thinking about the idea that why is not much research on developing and using your own IaaS than making use of the public cloud. Even the government are against building your own. (Like the UK Cloud first Policy which is main public cloud first policy so to say).

I am really interested in organizations that are adopting opennebula platform for their data center just to research on this area.
Please contact me if you are interested.