We'll have to agree to disagree. URL discovery is still a major problem, it's what made Yahoo as a human-curated index popular back in the 90s. In my admittedly anecdotal experience with seniors, many of them still have difficulty understanding the browser since they are task-oriented, rather than URL-oriented. And apps are task-oriented. URL bookmarks saved to the home screen help but are still prone to problems e.g. website alters the landing page and now the browser returns a 404. No problem for us but a very jarring experience for seniors who don't know URI.

And Gruber's point is that web apps still require internet access to work, albeit with improvements like cached storage in HTML 5. Whereas apps on the mobile device already work and are already taking advantage of sensors onboard the device, but the internet (cloud) makes them even better. For example, Garageband for iOS would be really hard to do as a webapp. Not impossible, but hard.