Adding an offering of developer blogging seems like a slam dunk if they want to continue being a fixture of developers world wide. Arguably it's not so great for other alternatives (GitLab, BitBucket, etc) and more lock-in is probably not great, even if the garden aren't locked around us right now.
[0]: https://docs.github.com/en/github/setting-up-and-managing-yo...
Whether I/we can blame them or not, it does feel good that there are some other business models in the space, I personally am a huge fan of GitLab[0] (I pay for an upgrade membership though it's nothing crazy), and on the more home-brewed front there's HN darling sourcehut[1]. Honestly if I was a GitLab project manager that browses HN... I might try and shark this idea -- you already "pay" for Gitlab Pages, why not streamline it, offer a netlify-like experience on top of it and try to get there ahead of Github?
[EDIT] - the "them" in "can you blame them" is intended to be the early Github team and/or their Microsoft equivalents. People like to put out good PR releases, but selling means something. The people who sold are aware of the the risks of selling and the loss of control/vision. Along with that realization/knowledge I think it's expected for them to have felt some fatigue/been expectant of some recompense for supporting open source as much as they have over the years.
I was moving from Medium (not a fan of their paywall practices and medium.com posts tend to fare poorly on HN). Didn't know dev.to existed until after I tried out HashNode. Didn't consider self-hosted as I just couldn't be bothered.
[0]: https://dev.to/pnehrer/a-story-of-rusty-containers-queues-an...
[1]: https://this-week-in-rust.org/blog/2020/08/26/this-week-in-r...
The difference between user generated content and curated content is a big enough differentiator that I don't think it'd be a death sentence.
I've fired up and taken down multiple attempts at blogging, I don't know if anything I've written was worth keeping but still, the information is lost.
I think this battle could be won in the tooling -- if all/most of the static website tools that you'd use support RSS, you can expect that it will show up (Hugo, Gatsby, VuePress, etc).
[0]: https://gohugo.io/