Follow the money. Android and iOS are developed by companies for whom decentralization is largely incompatible with their business models. There's no incentive to make it work smoothly.
That's probably also the same reason why there isn't any local peer to peer file sharing software for phones. Sure it would not be quite as amazing as bittorrent, but at a college campus you probably could still get all the music and movies you want without any real fear of legal repercussions.
You can do that with Bluetooth. And since Android 4.0, you can use NFC to automatically pair two phones, and then share between them through Bluetooth. It's called "Android Beam". Samsung modified this technology to work with Wi-Fi, too, and I think you could already do that before with "Wi-Fi Direct", you just had to pair them manually.
I haven't looked into 3rd party apps, but I imagine they could use the same protocols as Firechat for file sharing. But I think on Android it would only work through Bluetooth anyway. Google needs to mandate all OEMs to use Wi-Fi Direct otherwise.
Had not known of Firechat, yes ideally I would want an ad-hoc mesh network network, with peer to peer file sharing, not just one-to-one as Bluetooth allows. I think there is some support for mesh networking in place for Wi-Fi but have not looked into it since a long time (ca. 2007).
