XP had no real competition. Windows 8 faces well entrenched competition, much of it brutally undercutting MS on price and offering considerably better integration with their smartphone of choice (unless you're the %4 of smartphone users on WP7).
I blame Verizon for my not having a WP7 phone. I refuse to switch over to AT&T and Sprint coverage is hit or miss in my area, but I still hold a grudge over Verizon for not offering a better WP7 device than the HTC Trophy.