I do work in the consulting/deployment field and the feedback from our Customers are 100% clear.
Put the start-menu back or we won't upgrade.
Unless a company is willing to completely ditch the Windows platform for another OS, then sooner or later, they will
upgrade, Start button or no Start button. They can't keep running Windows <whatever> forever because at one point it will eventually reach its End of Life and MS will no longer support it, provide patches for it, etc. That's not much of a big issue for home users, but it certainly is for corporations.
I, too, work in corporate IT and I know about the effort and costs that would be involved in updating all the documentation, Help Desk training, etc., but at one point the budget and justification for the upgrade will be there and it will be undertaken. Sometimes that justification is driven from the outside: For example, if you have peers/competition who have upgraded to Windows 8, have issued Windows 8 tablets to their mobile employees, and have seen increased sales/productivity/profit, how long can you continue to stay idle and stubborn while your peers/competition either catch up or continue to surpass you?
We certainly aren't there yet with the mass adoption of Windows 8 and the Modern UI but it will happen and there are those corporations out there that definitely do not want to be caught left behind the technological curve.