I did not mean to say bitchat does the same, but that mainstream technology moved away from direct p2p, that could have evolved to sth like bitchat, to mediated modes of communication. Instead eg mainstream technology going from 1-1 IR to a p2p mesh architecture of communication (with modern bluetooth having higher range as IR etc), we got cloud, proprietary platform-specific protocols/apps etc.
Standardizing a non proprietary chat protocol over BT would be a pretty interesting prospect.
Who would advance it? Can you even get multiple parties to agree on what's in it? Is there any identity required? What's there to stop this being another "Bluejacking" vector but now with dick pics?
Given all of the above the proprietary route seems inevitable, even for protocols over Bluetooth.