The article (though it's very poorly written and unclear) seemd to suggest that this only applies to the standalone purchase installs, not the (usually, identical) installable versions included in Office 365 subscriptions.
Is enterprise adoption of Windows 10 a real thing? I've yet to interact with anybody who uses it at work, but I don't work for a big company any longer. (Although the big company I used to work for is for sure still using Windows 7.)
Yes. From 7 to 10 (recently or near future) is common.
I work at a fairly large engineering company and we've started to roll out Windows 10. The policy here is that no existing hardware will be upgraded to Windows 10 (at least during 2018), but that all new machines will have Windows 10 starting this year.