[Not smartphone users? These still exist?]
Remind you that there are always grown-up who have never had a phone yet, and that's the major target I suggest Microsoft should have targeted.
And the easiest way to get attention from them is games, especially games made to work better on WinPhone (Don't make it exclusive on WinPhone... those who know how to fish will tell you how important it is for waiting "fish" to get caught by hook first). I know a few people who take the pain to switch from Android to iPhone just because characters in iOS version of a game named "White Cat Project" can dodge easily but those in Android version cannot. Don't underestimate the influrence of number and quality of games on the mobile market.