> It’s such a well developed and mature project. I can’t believe it’s not eating Slacks lunch.

Zulip was acquired by Dropbox before it was publicly available, and then after a few years Dropbox spun it out into an independent OSS project.

It's kind of unfortunate that Dropbox never really gave Zulip a chance, because that was just before Slack became successful. Zulip as a product is way better than Slack and could have either "won" or influenced Slack and competitors to adopt a better conversation model.

Of course, nothing is stopping that from happening today, but by the time Zulip was refounded and regained momentum, several critical years had passed in between and Slack was much further ahead in market share.

Having used Zulip, Slack is now literally painful to use, especially at scale.