[SllX]

> video calling, audio calling, screen sharing, file sharing, permissions, media files

Back before Apple dumped half the features and renamed it Messages, iChat had literally all of these features and then some and it was fast. It was efficient. It didn't run my CPU up to max no matter how I was using it nor how much, and it used very little RAM for an application in its class. It ran very well on hardware that Slack would choke to death.

Slack is the way it is because Slack has other priorities above being fast and efficient, it's not inherent to the nature of a chat app with AV calling, screen sharing and file sharing (file sharing was table stakes for a chat app even 15 years ago or more).