Why are there no compelling upgrade options for Windows Phone? (US AT&T)

Is anyone else in the same boat here? I have an upgrade but there is nothing compelling to upgrade to.

Purchased the L900 new on contract on AT&T (huge fucking mistake by the way) April 2012 and then a L920 off contract when it came out because the 900 was so pathetic. Fast forward 18 months and there's still nothing notable to upgrade to. L925 = same processor and performance, L1020 = same processor and performance (camera on 920 is good enough for me), L1520 = ridiculously big and not a realistic option.

So there's nothing. How do they expect people to stay in an ecosystem when they don't come out with compelling new phones every year on every carrier? Are we really expected to wait until November another 5 months from now?