Interesting to think of the back and forth of complexity here. Now I can build my own version of slack that only has the features my team needs, and all the features work exactly the way my team wants it, but I need to write integrations so it works with a bunch of other software, and I need to understand the right way for those integrations to work, and by the way I'm integrating with a bunch of other custom software, and understanding the use cases for all that software is too complicated for just one person so we need multiple "software managers (product manager/developer combo) to manage all that software, and we need a place to run and people to understand how to run it on our completely custom container orchestrator that works exactly the way we want.
And maybe we lose some of the benefits of a shared ecosystem where we all run the same software with the same workflows an the shared plugin systems. And I do think this is a relatively likely outcome, because I think there's something inherently human around wanting to adapt the software to yourself rather than adapting yourself to the software.
It will be like this but in the millions:
https://xkcd.com/927/