[seanp2k2]

Since Slack's main business is chat, they have a pretty good incentive to get everything working again ASAP. Here's their SLA for "plus plan" and Enterprise plan:

  Our Plus plan Service Level Agreement (SLA) guarantees a 99.99% monthly uptime1
  We’ve designed our SLA to be simple and transparent — based directly on the information we make publicly available on 
  Slack’s System Status page.
  If we fall short of our 99.99% uptime guarantee, we’ll refund customers on the Plus plan 100 times the amount your 
  workspace paid during the period Slack was down.

Source: https://get.slack.help/hc/en-us/articles/204113126-Plus-plan... + https://get.slack.help/hc/en-us/articles/115003205446-Plans-...

Chat is a commodity these days. For most businesses, it probably makes more sense to just let the companies in the business of offering paid chat services do their thing.