Bad luck, I'd have to say. I'm still quite happily running my original iPhone 2G and the home button is extreme solid.i wish they'd improve the home button. it feels like crap compared to the ipad's. i've used about 8-10 different iphones, and all had cheap feel home buttons. you press them, and they don't press evenly. they always sink to either left or right side, never straight in the middle.
Oh, and for everyone else, you realize that anything you have to say is completely invalidated as soon as you throw out the "fanboy" card? That word essentially just gives the rest of us license to laugh, mock you, and ignore anything you ever post again.