The IRC protocol is in a different situation to USENET, because the latter has many different independent, individually federated networks of servers, whereas the latter has just one.
This means that server-side innovations can and do happen - they just need to respect the basic server-client protocol. Often the newer features are delivered through "services", which means they're in-band signalled.
IRC is like USENET: It has barely evolved for decades, nobody can profit by improving the protocol as it's a commons, so it just stagnates and dies out.
Eventually all the decentralised protocols that were born in the early days of the internet will be gone.