What users need is not more choice; as Marco said, the App Store is crowded. What users need is higher quality apps, which iOS 7 will purportedly enable. Therefore, developers who take advantage of this opportunity will make more money than those who don't.

I am using the beta on my primary phone, and I am starting to see what Marco is talking about.

There's a fallacy in your reasoning: that quality wins.

This isn't always true. Word of mouth is a much more powerful force than raw quality. Look at eBay, for example.

Most apps luckily don't have many network effects. But I won't be switching PDF readers just because the new one looks more like iOS 7.

I agree with you, although I think that Apple is betting that "looks more like iOS 7" is more like "works better thanks to features only available in iOS 7".

See this tweet by @flyosity:

"Damn, the UIKit animation/dynamics effects in iOS 7 are some seriously futuristic stuff. Can't wait to see what people do with it."

https://twitter.com/flyosity/status/344642697241436160