[iv597]

Name recognition, employee familiarity (I've used Slack at every job I've worked since early 2015, I pretty much know what to expect from it always), and punting maintenance costs (this is probably the biggest factor).

I love IRC and XMPP. I'd love to run one of those, or some new service (Matrix?), at work. However, my time is arguably better spent doing anything _other_ than maintaining such services, and the same goes for most engineers at most companies, sadly.

Side factor: the mobile clients for IRC and XMPP almost universally suck, at least on Android. I imagine if those problems had been solved in a reliable way, more companies may consider them (assuming the allocation of engineering resources problem isn't a problem).