Experience in OpenStack sometimes comes the hard way
The key words are, "companies ...with ample engineering resources, experienced in OpenStack..." This is code for a small handful of companies that have bought their experience the hard way, through experiment and early trial and error implementation. They include PayPal, Comcast, The Gap and others. But there are not that many the meet the description. Their "experience in OpenStack" tends to come from Mirantis, Red Hat, Cisco or other third party vendor.