Wouldn't the main difference be that iOS and Android come with a very complete and high quality default UI toolkit? It's easy to build a decent app using just t

Wouldn't the main difference be that iOS and Android come with a very complete and high quality default UI toolkit? It's easy to build a decent app using just the system libraries, whereas on the web you're pushed to reinvent the wheel from the very start (how do I load my CSS?). Technology churn is also minimal in comparison. Anecdotally, my impression is that mobile-focused designers are much more attuned to interaction design than their web counterparts; much easier to build nice UIs when they have been fully thought out.