Re: "Cupertino idiot tax"
"Macs are really not good ROI."
Tell it to IBM, Cisco and SAP. Hundreds of millions of dollars ROI.
"How much of British Airways or AXA desktop/laptop estate is running on Macs?"
BA and AXA use iPad throughout the client-facing side of the organisation, as well as backend integration services and MDM. You're assuming Apple starts and finishes with desktops and laptops.
"In most companies they have one or two Macs"
And that's your considered, evidence based opinion? See the difference between you and me, is that I actually know what I'm talking about.