I'd say that Microsoft is doing this precisely because of this bit from the article: "the number of PCs still running Windows 10 is likely much higher than execs in Redmond would like."
It's in Microsoft's best interests to do what it can to make the Windows Ecosystem (all of it) as secure as possible. We all know that once the ESU program ends that there will still be who knows how many millions who will not do the updates to their hardware to make Windows 11 compatibility possible. Once security patches stop that's when "the feeding frenzy" will begin. Another year allows for quite a bit of actually antiquated hardware to "die a natural death" and be replaced.
Ultimately, though, I'm dreading the end of the ESU because of what's sure to be unleashed after Windows 10 is out there, unpatched, and every blessed attack surface that can be found will remain available. Ugh.