I think part of the problem is that there are a lot of integrations from Slack that aren't available on Mattermost. You can certainly make the argument that tho

I think part of the problem is that there are a lot of integrations from Slack that aren't available on Mattermost. You can certainly make the argument that those integrations won't be developed until more users abandon Slack for Mattermost, but for some it's not worth the loss of functionality.