Telepathy was designed as a framework which could have various
"Connection Managers" (in the telepathy terminology). A Connection
Manager is responsible of doing the actual communication with a given
server through a given protocol. Telepathy has connection managers for
XMPP, SIP, IRC, etc... see [0]. For instance, Polari uses Telepathy
for the IRC protocol.
All in all, if desirable, Matrix and GNU Ring could be connection
managers in Telepathy instead of standalone bits.
Specific clients could be created backed by Telepathy, e.g. no need to
rely on Empathy.