Why is my iPhone no longer working on the Bose sound dock with the case on?

I was able to use the sound dock with my iPhone 4 case on, but now I have to take the case off for it to connect.

It's probably not designed to plug in with the case on, and the terminal connections have worn a little. (terminals designed to be connected, disconnected, connected. So on/so forth) have wear engineered into them, and expect a little wear, just maybe not a case displacing the connection up to 1/16" (guess). Pins in all terminals eventually fail from repeat usage and wear. That's my hypothesis!

It's due to the mistake of design.