500kB is the size of the web frontend. To that you'd need to add the web browser, the backend, and whatever runtime the backend needs. It's unlikely to be any less than 10MB.
Meanwhile I can just write a IRC client in C that's less than 100kB.
And then you need an irc bouncer as well though. And still don't have a fraction of the features.
As somebody that used irc a lot in the day, it's ridiculous to suggest that a protocol that doesn't even save chat history is being compared to the feature rich chat apps of today.
Meanwhile I can just write a IRC client in C that's less than 100kB.