As far as I am aware, Apple does not seem to have a policy preventing this type of work. There was a fairly well-publicized release of an experimental codebase from Ericsson:

http://labs.ericsson.com/apps/bowser,

which has since been retired (although as far as I know, not due to any conflict with Apple):

http://labs.ericsson.com/blog/retiring-bowser.

Apple needs to allow serious browser competition on iOS. But of course they won't until more developers and users start asking them for it.

Forgot about that one, thank you. Another one on the list, unfortunately.

WebRTC does not currently exist on the desktop Safari either. I'm sure if a 3rd party wanted to implement WebRTC in a browser for iOS, they are probably welcome to do so.

That's a different layer - it runs on top of an already established network. This is about establishing some kind of connection.

WebRTC also requires a central server for discovery (typically overy HTTP I think?). It maybe possible to replace that with Bluetooth LE, but then the WebRTC connections to each other will need to run over an TCP network.