strictly speaking, it never was part of windows, or came bundled with it from Microsoft. Our first family windows computer (Win 98) didn't come with an office license, instead the manufacturer included only "Word" and "Works" as a "value add". It was a separate piece of software that we could install (or not if we chose to).

Up to including windows 7, every single computer any of my friends and family purchased came only with a windows license, If they wanted MS Office, they had to buy the license separately and install the software package themselves. Sometimes it might have come preinstalled as a trial, but that still required purchasing a license after a set amount of time (usually 90 days, I believe), and it varied from OEM to OEM, as did their other bloatware (Norton, Eset, etc.).

I have only noticed Windows installing office out of the box with Windows 10/11, where they install the app from the MS store during the initial setup - I assume they started this on Windows 8 as well, but I have only seen PCs being upgraded from 7 to 8/8.1, never a fresh install.

But even then, it's just a limited trial for their office 365 suite.