If you think Microsoft was unopposed in their courting of Nokia, you'd be wrong. According to Google (still) CEO Eric Schmidt, they did attempt to get Nokia to use Android instead of Windows Phone 7. Schmidt refused to go into details when questioned on the matter, but did say that Google talked to Nokia to encourage them to join the Android Army.
Google hasn't given up either. Schmidt expressed hope that Nokia may come around one day, insinuating that Windows Phone 7 might not work out for the Scandinavian company. It probably comes down to the financials of the deal. Microsoft is reportedly paying billions to have Nokia get on board with their mobile vision. Google just makes the software, and their financial ties with partners are not as strong as they are in Redmond.
Do you think Nokia will one day give in to the little green robot?