I don't think most folks will hold onto their S6's for years. Although they are sharp looking phones, I'd love to have one with W8 on it.
I also get annoyed by the repeated calls for WP flagships. However, seeing the press that gets generated by new Android, and especially, iPhones, I understand why Windows enthusiasts are itching for a true flagship. Once we get one, it will hopefully give us something to brag on. My BLU Win HD is a good budget phone, but nothing I can brag to iPhone or G3 users about. Also, I'm on T-Mobile and my only options for high-end Windows phones fewer than 2 years old were unlocked phones. That's not the worst thing in the world, but it's not as easy as having something that works with your carrier out-of-the-box.