Atom still had a healthy number of active contributors (presumably most of them were from GitHub) making improvements to the product on a daily basis to make it a perfectly viable tool for the people who chose to use it (and despite the much smaller developer base they continued to innovate with projects like xray and tree-sitter)... That is until the Microsoft acquisition happened.
Before anyone jumps in with the causation vs correlation argument, I think any reasonable person looking at the evidence would agree that the timing is convenient enough to make it highly unlikely to have been a coincidence, especially considering that most of those contributions were from employees at GitHub who were _getting paid to work on Atom_, so the only reasonable explanation for the contributions to stop abruptly within a month is that they _stopped getting paid to work on Atom_.
To add insult to injury they even had the audacity to claim they wouldn't do exactly what they did. That is the crux of my issue with how they handled this acquisition.
But the words of the linked Reddit comment from Nat Friedman were "we will continue to develop and support both Atom and VS Code going forward"; that's a true statement today. Atom is currently being developed and supported. That's a case of adhering to the letter of the statement rather than the spirit, I know. But that circles around to the problem of VSCode's rapid ascent in mindshare -- if your company ends up owning two very similar editors and they both have roughly equal downloads and community interest, you might try to support both equally. But if one of them has orders of magnitude more downloads and community interest than the other, you're going to focus your efforts on the popular one.
It's quite possible that this was just a random side-effect from a shift in focus, instead of a planned sabotage.
If commit activity graphs are really a meaningful measure, look at VSCode's:
https://github.com/microsoft/vscode/graphs/commit-activity
The number of commits per, uh, date unit (the graph is not super clear on that axis, honestly) across the entire length of VSCode's activity graph rarely drops as low as the highest number of commits per date unit for Atom.
I'd have preferred to see both survive and do well, but that really hasn't been the way the text editor space seems to have worked. Editors that are conceptually awfully similar to one another tend to have one dominant player: TextMate (at least for Macs), then Sublime Text, then Atom, then very quickly Code. Given that Code and Atom are probably the closest of any two in that list, this just isn't that surprising.