Two things about cars:

1. No one touts a single model as an [once] innovative, "simply works" car that has everything you need. Now the iPhone's lost ground, but what happened with the iPhone is people started looking at your Toyota and going "Is that a Lexus?" Seriously? It's a car, and specifically a Toyota, but thank you for noticing it's a new vehicle I recently purchased.

2. Most people don't buy the next year's model of the vehicle they already have, because the next year's model ultra rarely (ever?) has anything worth wasting money like that. Most cars can live 5, 10, 15 years or more before you need a new car. Probably at least 5 before features change enough that might warrant it, or maintenance becomes such an issue it becomes necessary; ideally that'd be closer to 10+. Same with phones. You can buy the next model (e.g. Samsung Galaxy S, S2, S3, etc), but is it worth the price? Or should you wait 2 years and pay an upgrade fee (far less than full retail), if not longer?

As for shoes? Well that varies, but they can wear out in less than a year -- usually because of crappy craftsmanship so, yes, buying new ones every year or two happens. They also get worn down from daily use; phones have less of a problem of wear unless you consider the gradual decline of batteries. Both products would ideally last longer than one or two years, but that certainly isn't guaranteed anywhere.

Phones should have a certain amount of longevity to them. Doesn't stop people beholden to any make and model or OS from deciding to upgrade annually, of course. Their money. Same as if someone bought a new car every year -- though that'd be a worse idea by far given the 'return' on selling the prior vehicle and for considerably less (I mean the iPhone 5 does at least come with LTE, so that's one feature people might really want the iPhone 4 didn't have; might be worth the $200 -- not that they'll get any more data allowance from their favorite carrier for all that speed).