On-premise (1960-2010) -> Cloud (2010-2026) -> On-premise (2026+)?
If this mattered to them, they wouldn't be running so much in the cloud or in proprietary software that they have no ability to air-gap.
If companies ever cared about this, Windows would not be dominant on the desktop.
As to why Windows is so dominant, I'm as clueless as you.
I wonder if that's because they don't know better or because of a lack of trust or costs?