It's a chat app that integrates to most other services you use and ends up being the most extensive repository to all of the information shared inside your comp

It's a chat app that integrates to most other services you use and ends up being the most extensive repository to all of the information shared inside your company. As someone who pays for Slack, it would be VERY hard to make a switch. The impact of this in retention and opportunity to monetize the 'integrate workflows' increases the multiplier. Salesforce has probably calculated how this opens up revenue to their existing product line and Slack itself is growing. I'm not saying this is science but is part of the rationale that goes into the price.