Their sales teams have been locking in all major corporations. I have no idea how they cornered a market so fast. They are living like kings right now.
Chat is mostly ephemeral, so there isn't much lost in switching providers even at large corporations. If a better chat app takes off in the next year there isn't much stickiness in the current app, especially when individual teams start using the new product. This is how I've seen both AWS and Slack become standards and large corps–the innovating teams start using it regardless of the corp standard.
You talking about Salesforce? They've been around since 1999 and have been dominant in SaaS ever since the phrase was first coined. There's nothing fast about it.
