Apple already provides some amazing documentation and tutorials for making offline-capable mobile web apps, but they're still treated by Apple as the bastard cousins of "real" iPhone apps. They should buy or provide an officially-supported analogue to a tool like PhoneGap[1] or Titanium[2], allowing HTML5 apps to appear in the App Store, and perhaps provide an Apple-supported framework such as their mysterious PastryKit[3] or contribute to SproutCore[4], giving HTML5 developers better tools to conform to Apple's HIG.
HTML5 apps built on open standards should be on an equal footing with apps built in Cocoa Touch. That would be walking the walk.
[2] http://www.appcelerator.com/
[3] http://daringfireball.net/2009/12/pastrykit
[4] http://blog.sproutcore.com/post/531215199/introducing-sprout...
EDIT: "officially-supported analogue"
EDIT: footnotes