Ctrl+S only does that if a document is unsaved, and it still doesn't actually take you to the save dialog. It takes you to what Microsoft calls the "Save As menu", which takes up the whole window, causing the document content to be obscured, and requires a mouse click after that to get to the actual Save As dialog.
For mouse users, getting to the Save As dialog is actually three clicks in recent versions of Word. F12 is just so much more convenient.
It's still "File -> Save a Copy" (2 clicks) and I'm on an October build that's as new as it gets externally as far as I know: 2210 Build 16.0.15726.20188.
The overlap of "users still using Microsoft Office" and "users using local storage" declines with each passing day. IT admins don't want data outside their retention policy/access logging/subject to user hardware failure, and anyone who thinks cloud storage is a malicious big tech plot left the Microsoft ecosystem years ago.
Even so, using OneDrive as a backing store for user documents has been integrated into Windows for a while now, and every app that uses standard file save dialogs etc ends up automatically and transparently doing that, so why should Office be special?
I don't think everyone using office in the workd is "under" an IT Admin supervision, many home users and small businesses still use Word and Excel (and local storage), I believe.
Your statement means nothing when Microsoft is using dark patterns to funnel users onto the cloud. Of course the numbers are going up, that in itself does make it a good thing for users.
For mouse users, getting to the Save As dialog is actually three clicks in recent versions of Word. F12 is just so much more convenient.