Yeah, this is ridiculous because all the cool apps in the world can't overcome the fact that they are only available on a single device. What makes web applications great is the platform and location agnostic nature of them.
App coolness is not a function of the number of devices it runs on.
a) people probably buy iPhones because of specific cool apps that are available on it (similar to the battle between the 3 game consoles)
b) an iPhone user doesn't care whether the cool app they love run on a Crackberry. I suspect Android users also don't care if an app they love doesn't work on an iPhone.
This is certainly true for apps that take advantage of the hardware. The thing is, a lot of apps out there just encapsulate web functionality inside an app so for those not so much.
HTML5, if 'fully' supported by browsers (like Safari and Chrome), supports a bunch of new features that make previously impossible stuff easily doable - the major one being offline storage.
e.g: GMail can store your inbox in your browser's offline storage cache, so you can continue to use the site and send/read emails just like you do with Outlook or other mail clients today. When you reconnect to the web, it'll sync up and send the differences.
