The barriers to a true mobile browser are several, and many have been addressed here. One that has been overlooked is browser plug-ins. Flash, CSS, Java, and several other technologies have been slow to be adapted to mobile devices. While many of these are here now, or just around the corner, there are some that will take a while longer to hit our phones. While the technology gap exist between mobile and desktop browsers, so will the adoption gap. Just as there will always be a bandwidth gap between wireless and wireline. Sure 3G, WiFi, WiMax, LTE, 4G, etc. promise impressive speeds, but landline companies have not sat still. Comcast, Verizon, Qwest, and other providers are uping their speeds significantly in the last couple years. Now, as geeks, we all have our love/hate opinions of our monopolistic landline internet connectivity providers. The fact remains that speeds are improving here too.
Personally, while I think the mobile platforms will improve, I think there will always be a unique set of needs for mobile browsing, and a distinctly different set of needs for desktop browsing. Granted, there will be a huge overlap, but not a total overlap. I surf on my mobile devices as much as I do at home. With that being said, I surf very different things on each device.
Mark