I've never heard of Skiff, but it's sad to see more software gobbled up by VCs. Though it sounds like the back end was never OSS to begin with?
I used to be so excited about a future where people were software literate where we would be building open systems and make a decent living. Instead, people have been force fed locked down systems in the name of "user experience", all so that a few people can make an absolute killing while the rest of us feed off the scraps (even if the scraps of the software industry are still pretty good). It just makes me sad.
I am extremely appreciative of folks who do make honest open source software though! Many of them do make a decent living too. It's hard not to lose hope when reading stuff like this, but then I remember that I'm typing this comment using Firefox on KDE Plasma running on a Linux kernel, right next to an Emacs session. Sticking to good open source software is a wonderful thing!