Our entire company switched to Slack within basically a day. While that's a big selling point for Slack's ease of use, it also means it'd be easy to switch away to a competitor within a day too.
My team has built numerous chatops bots and automation around Slack, mostly because of their great API. In a way, we're building our own lock-in, as any replacement would have to provide the same level of API access, from in-channel announcements to channel scraping for parsing by other systems. And it would require retooling the bots too.
What about using something like the Microsoft Bot Framework(1)?
I am not too familiar with it but its open source and it looks like it works with Skype, Slack, Facebook Messenger, Kik, Office 365, etc.