How Big Is Mobile Banking's App-etite?

I have to admit, I have app-envy. Owning an old Windows 6.1 Motorola mobile phone, I look on with a certain longing at my friends, colleagues and fellow airplane passengers who enjoy endless, happy hours with their iPhone/Android/Blackberry "iBeer" apps. I am even more jealous of their mobile banking apps, which seem to me the coolest retail banking technology ever. But truthfully, I am beginning to get a bit dizzy contemplating the options that await once I finally trade in my current mobile device. At the last count I saw, the iPhone App Store had 120,000 apps. This got me to thinking about the plight of banks offering mobile solutions, which are increasingly feeling the pressure to keep up with the app explosion. A very quick check on Wikipedia revealed the following:

• There are about 6 versions of the iPhone OS (operating system), with a new one in beta
• Since April 2009, there have already been 3 versions of the Android OS
• There are at least 30 versions of the Blackberry OS, more if you include those for the Canadian market -- I stopped counting, but see for yourself.
• The Windows Mobile OS has been around for a while, but it's probably safe to say that phones with 5 or 6 versions are still in use
• Let us not forget the Palm and BREW OS'

Yikes... Undoubtedly, more of the above will come. I'm no developer, but common sense dictates that this is a lot for a bank to keep up with. Prioritizing, developing, maintaining and owning apps for a myriad of operating systems and mobile devices has got to be daunting and expensive. In recognition of this, some banks are just creating apps for the iPhone, which often constitutes a large number of mobile banking users. But what about addressing all the other phones and OS' out there? It would seem to me that a bank has two choices to keep up with apps. The first is to outsource work to a vendor, whether a full-on mobile banking technology vendor, or an app "development shop". The second is to provide a minimal level of apps (say, just for the iPhone) in the nearer-term, and wait for a "post-app" era in the longer-term. HTML 5 may have the potential to enable mobile browsers to offer the same functionality/integration with a phone's native capabilities (e.g., locationing) that apps currently perform. In either case, both banks and vendors have a lot to think about in terms of development roadmaps. Again, I'm no developer. I would love to hear from our readers. Are apps here to stay? Will HTML 5-enabled browsers eventually usurp apps? Is there some other approach that can replicate the attractiveness of apps?