But that's how IRC was originally designed, and it didn't work out in the long term.
There was only one network and any server could join it. But you could set up malicious servers can cause havoc on the network. Eventually all the Hubs but one closed their doors so only authenticated servers could be added. The remaining holdout was eris.berkeley.edu
And so the network split into the Eris-Free network (or EFnet) with the remaining servers connected to eris forming the Anarchy network (or Anet). Anet died out reasonably quickly.
There have been a few more splits over the years, until you reach the current situation, with around 6 major networks and hundreds of smaller networks.
There was only one network and any server could join it. But you could set up malicious servers can cause havoc on the network. Eventually all the Hubs but one closed their doors so only authenticated servers could be added. The remaining holdout was eris.berkeley.edu
And so the network split into the Eris-Free network (or EFnet) with the remaining servers connected to eris forming the Anarchy network (or Anet). Anet died out reasonably quickly.
There have been a few more splits over the years, until you reach the current situation, with around 6 major networks and hundreds of smaller networks.