If this leads to a mass exodus from Freenode, it'll probably significantly reduce overall IRC usage.
Communities will fracture, people will set up random splinter networks that will die off in a few months, and lots of open-source projects that already want to be using something Javascripty like Slack or Discord are going to use this as the motivating thing to make the switch.
Personally I'm staying put on Freenode because I don't see a lot of user-facing impact potential here, and IRC was already essentially untrusted/public (yes, even your private messages - you don't really know who is relaying them and how trustworthy they are).
How many would move to Matrix?
Why does it matter? Matrix is no IRC. Fewer clients, way more complex protocol, the identity server is centralized, only one complete server implementation exists (and it seems like that's the only one that will ever exist, other attempts appear dead, despite the list on matrix.org) and worse than Freenode being owned by private capital, all of Matrix is controlled by New Vector LLC -- the protocol, the clients, and the biggest servers, and they operate the main identity server so they can keep track of your phone number or email address and map it to your Matrix ID. (I wonder when they'll start selling that data?) If this situation with Freenode makes you move to Matrix you're choosing to move to a network with all the same problems you're fleeing, but magnified
Oh but there's one more thing about Matrix
If you don't like it, the CEO of the company will come argue with you about it here
I don't check for replies to my comments on HN because this community is too toxic but I'll bet Arathorn eventually comments to tell me I'm wrong. Maybe he'll promise that they don't sell the vector.im identity data. I don't trust him, anyway.
Even if you don't check, other people should know that this is extremely misleading.
> Fewer clients, way more complex protocol
This is actually a valid complaint, though it's partly due to Matrix being pretty young. The other part is that Matrix does a lot more for you than IRC (eg e2ee and federation) and those extra features require complexity.
> The identity server is centralized
This is a completely optional part of Matrix. You don't need identity servers. You never have to provide your phone number. They don't even push you to when you sign up. It exists as a convenience feature for people who complain that they need to be able to discover their friends on Matrix by their friends‘ phone numbers. Also, you're free to run your own identity server for you and your friends or whomever.
> other attempts [at creating a homeserver] appear dead
This one is way off. Synapse, the "one complete server" you must be referring to, is going to be deprecated. The Matrix Foundation team is working on Dendrite to replace it. There are also several independent projects that are very active, notably Conduit, started by one guy unaffiliated with the Matrix Foundation team. Conduit is extremely far along and is under constant development.
> All of Matrix is controlled by New Vector LLC
The people who created Matrix were careful to separate their for-profit projects from FOSS community projects. Matthew Hodgson (Arathorn) explains it well here [0]. TLDR: The Matrix spec, the Element clients, and the Synapse/Dendrite homeservers are maintained by a nonprofit. Same team, different organization and funding. Everything is open source, so anyone is free to fork at any time.
> This one is way off. Synapse, the "one complete server" you must be referring to, is going to be deprecated. The Matrix Foundation team is working on Dendrite to replace it.
Interesting, I've always been reticent to host my own instance because of how complex Synapse is to setup for the uninitiated. Hopefully Dendrite makes it simpler.