Well, then we can all turn off our computers and go home, because something that "works" is obviously good enough and the entire software industry doesn't need to exist anymore. Most things we have today "work" but we're still improving on them because "good enough" isn't good enough.
The question you're not asking is whether your replacement is better than the existing solutions. Slack isn't. It's closed source, proprietary, and tied to a third party's servers. I'm not going to tie my projects or company to that kind of anchor.
