Re: Do some reading!
"Azure Stack is about havine MS Azure in your own data centre. Nothing to do with hosting in the cloud as we currently understand it."
Well it is - it's hosting in your own private or hybrid cloud. So whatever you do in public cloud in Azure you can always choose to bring back on premises. Google and AWS simply don't have an equivalent solution.
"It's be 'coming soon' for years."
No it's been shipping for a while now:
https://azure.microsoft.com/en-gb/overview/azure-stack/integrated-systems/
Biting the hand that feeds IT
