I would not say the exact same about HipChat, any more than I would say the exact same about Microsoft Teams.
I've had the (fortunate?) opportunity to use both, and neither of them feel like they do as good of a job.
I even used HipChat first, so it's not just bias. (Wanted to stay in Atlassian tools)
So perhaps it's just the added polish Slack seems to have?
I know the Hipchat for Android app was god awful. Just the worst.
Microsoft Teams didn't consistently scroll down automatically for new messages when you were already at the bottom for quite some time - supposedly that's fixed now.
Perhaps the example you should bring up is "MatterMost" - though I certainly have not used that.
IRC and Slack are nearly the same, but IRC comes with some overheads of finding or setting up a server, figuring out your own backlog, &c