I agree that the public cloud market leaders are AWS, Azure and GCE and that innovation is being done by the public cloud providers not the private cloud.
I think the majority of companies are happy to enhance their existing virtualized platforms than to install a private copy of a public cloud. Recently I was very impressed by the new converged hardware from companies like nutanix. While these are not low cost hardware solutions it is possible to easily run vsphere or open source KVM on nutanix and you can incrementally upgrade nutanix making it very powerful for the price. So the innovation in the so-called "private cloud" is probably more about hardware then software.