Agreed. I'm afraid, the famous quote about Dropbox from Steve Jobs about being a feature not a product is playing out. Dropbox doesn't even own the commodity they sell (as far as I know). They sell you on storage, but you receive a syncing service, not storage.
I like dropbox, don't get me wrong, but they need to recognize the core value they brought to the table (and may still have) is better user experience design, not infrastructure. Simply offering more apps that are bound by the constraints of one's Dropbox account seems profoundly myopic.
I agree with you that their core value is a better user experience. In my mind, offering their own apps is actually the natural continuation of this core value -- since the underlying storage is just a commodity, they can differentiate by having really well-designed apps that sit on top of it.
I like dropbox, don't get me wrong, but they need to recognize the core value they brought to the table (and may still have) is better user experience design, not infrastructure. Simply offering more apps that are bound by the constraints of one's Dropbox account seems profoundly myopic.