Yes, I read Jobst's book. I interpreted it to say that the spokes go under a constant cycle of tension and detention, reaching the peak tension at the top of the wheel and reaching zero tension at the bottom (where the rim flattens out as you say). The only reason the hub is "hanging" from the spokes on the bottom half of the wheel is because they are tight enough to still hold tension within the wheel. Really, that means they are pulling the hub downward, not holding it up. This only supports the wheel because it is keeping it from going out of shape (as would happen should all the spokes become slack) Since the fork is creating only a downward force (front wheel only here), if the load isn't shared than only spokes going UP towards the rim are actually supporting the bike, while any downward facing spoke can only be supporting the wheel shape, which indirectly supports the bike. In a sense, I am agreeing with some of your interpretations, but thinking that it's more dynamic than that.
EDIT: Did you mean that there are shared loads but that they are the same in radial as crossed patterns? If so, I agree with that completely!

Don, it is possible that it's the rim strength that is different, but I do think climbing and sprinting would cause a lot of forces to be exerted on the front wheel. Are they the same guage spokes?