I still think it will be hard to push Microsoft out of businesses. Aside from the reluctance to port software, many IT departments have an aversion to Macs because they have invested so much training in Microsoft. IBM found that Macs require less IT help, which could be a selfish reason to stay on Microsoft.
Finally, Apple is unlikely to make inexpensive Macs. Many businesses unfortunately have not learned that cheap doesn't last - or IT doesn't care because it helps justify their budget.