> Given that the author works at a large company, that has millions of machines, and where any swap change has cost implications in the tens of millions pounds, I suspect the article is based on data, rather than vibes.

Yes, but the author is most likely optimizing for a metric that I don't care so much in my per personal computer while dismissing metrics that I care about.

> It was always the case. but then a TB of disk isn't that expensive anymore.

But swapping out GB of RAM is expensive in terms of latency.