If you need functionality like you describe, ship a native application via an app store. It’s a much better experience than web development.
I have pretty much ditched native office suites in favor of google drive as well on my desktop system.
And things like Facebook hasn't even considered native desktop implementations.
So it is safe to say that the web is a great app delivery platform (at least on the desktop) and as such, I think it is completely reasonable to improve upon it and extend this benefit to mobile.
A side comment would be that you can make your webapp perform remarkably well on mobile, with things like HW accelerated transitions, local storage, etc...
On my end I don't want to have to download an app to do all the things I want to do. I keep as few apps on my phone/computer as possible.
Not all software development is making cutting edge social phone apps.
That is a faf when you want to be cross platform though. With care I can write an application that covers pretty much all the users I care to cover, i.e. those using desktop or mobile browsers released in the last few years. In fact there are a couple I intend to develop once I've got certain other things out of the way that are eating my "personal project" time currently. Yes native apps have advantages, and for my projects there might be native apps later, but developing for browsers first (well, API first with browsers being the first major client) gives the best use of your initial time unless your app needs greater performance, access to hardware, or something else not possible/practical in the browser.
If Safari lags behind to the point where I can only support iDevices as secondary citizens (web first, followed by native apps for platforms that need them) then I am perfectly happy to do that. Thankfully that is a practical consideration, at least for my projects, unlike at some points in the past where not supporting IE6 locked you out of a much larger part of your potential audience then not supporting mobile safari does now.
If enough other developers take this route (Your platform doesn't work well unless I create something specifically for it? OK, I consider that later when I've got everything else working) maybe the direction of Safari will be forced to change in that respect.