Your defense here is "Microsoft made this promise in front of a different group of people than the press with different financial motives than to get people to use windows so they shouldn't be bound by it"?

a) That's absurd, that's clearly still a reason they should be bound by it

b) That it wasn't in front of the the is clearly false given press widely reported on it, if it wasn't in front of the press they couldn't have reported on it.

c) That it wasn't intended to convince people to use windows is clearly false given Microsoft's simultaneous purely public facing marketing of windows as a thing that would be supported for the lifetime of the device... Microsoft's continued endorsement of the sentiment behind the quote, and Microsoft's decision to not disavow the quote when journalists no doubt asked about it.