They weren’t willing to risk current day (at that time) profits for a future selling fewer licenses.
That certainly matches their modus operandi. I would agree with this for the most part, but by 2010 they were already working on Office 365 and moving to the idea of Software as a Service. While Office 365 wouldn’t be functionally available to everyone until later in 2011, it was clear they had plans to work around having a license tied to a device, and instead starting to roll out Microsoft Accounts to which the licenses would be tied.