Sure, if you're Apple and you make expensive hardware, you don't want your initial release to suck. It's just too hard to make changes after the fact. Software, on the other hand, is cheap to produce. You can afford to release early and often, because releasing fixes and improving features is quite doable. If you release late and rarely, how are you going to improve your application? How are you going to know what users want? How are you going to know if your idea is headed in the right direction? Simple: you won't. You'll spend all your time, effort, and money building the wrong thing. At best you'll get a ton of users for a few weeks when you launch, and that'll be that.