They evolved into Instagram(8 billion), WhatsApp(20 billion) and FB(trillion)

No.

Chats did not evolve to social media.

Facebook is a descendant of hotornot not icq or chats.

Ws was seen as free sms.

Pretty sure discord and slack are not useless…

Discord and slack are evolutions of msn messenger and icq.

Not web chat rooms.

Discord is literally a web chat room. It operates over the web. Its interface is a re-branded web browser. You chat in it. There are rooms (although I suppose people call them "channels," implying a conceptual link to IRC).

In the 2000 every single webchat room was connected to irc.

Discord is not.

that makes absolutely no sense

msn messenger became Skype wich then became ms teams.