My problem is that instead of building FOSS tools to improve the interface to the tools we love and use daily (irc, gpg, irssi/erc, emacs/vim, screen/tmux, usenet, etc) what has happened is people like slack take advantage that the FOSS interface suffers and gives the standard user an easy interface in a proprietary system. There is no reason for slack to not be fully open and still offer the same stuff, my main concern these days is proprietary lock in, for a myriad of reasons including business and personal ones.
As the surveillance engine grows, those of us who have gone through the pains of open-sourcing our workflows will be way ahead of everyone else... but I fear we aren't addressing this main issue which is ease of use/adoption for general user cases.
And no, giving me an API does not make it open.
Short story; we need better FOSS UI/UX.