"You are counting on webOS being nothing more than a WebKit browser. I am sure that's not the case."
Even if it's not, the fact remains that apps written in HTML+CSS+javascript (what's more, HTML+CSS+JS tweaked to run on WebKit) will be trivial to port to the iPhone -- not just because the iPhone has a fantastic webkit browser, but because the apps themselves will be trivial.
The Pre, at best, will be a phone of widgets (I like your "slightly clever phone" moniker). I've made my share of widgets, and I know they can be both fun and useful. But after three months of game development on the iPhone, I would hang myself if I didn't have Cocoa. The Pre is going to see twenty versions of Lights Out, but you'll never see a Cro Mag or a Crayon Physics.
When people go on about the iPhone being a "computer in your pocket" they're talking about Cocoa its OS X underpinnings. Mojo and WebOS, at best, put safari in your pocket, and the iPhone already does that for cheaper.
Maybe you're right, and the Palm doesn't have the iPhone in its crosshairs. But I'm not sure how that helps them.