Slack doesn't have an on-prem option. Microsoft Teams doesn't have an on-prem option. What are enterprises supposed to use, RocketChat? Matrix? With no clear migration path?
Really poor move on Atlassian's part. It would be one thing to sell off Stride, it isn't doing well, work with Slack to have some kind of automated migration made available and let customers flip the switch. Maybe if Slack were to keep supporting Hipchat on-prem, or provide a migration path to a new Slack on-prem product, that'd be fine. But to leave HipChat on-prem customers out in the cold?
What's the next Atlassian on-prem product to get thrown under the bus? Bamboo for sure, it's been unpopular relative to Jenkins almost since its beginning. It's definitely surprising that Fisheye/Crucible get any support any more, or Crowd for that matter. But why not Confluence on-prem too? Do we have to worry that Atlassian will stop supporting Confluence on-prem in eight months because Office 365 keeps gaining marketshare?
Atlassian's continued long-term support for minor on-prem products was one of the signals that said, if you pay up for HipChat on-prem, we'll support you long-term, you'll be fine. Atlassian completely shattered that with this announcement and eroded a lot of trust that enterprises were putting in them. Big shot in the foot here.