So the same software exists on multiple platforms, there are no legacy or hardware compatibility considerations, interoperability considerations, no budget considerations, and the users have a choice in what they use?
I.e the same functionality exists with no draw backs and money was no object.
More choice in hardware. More flexibility in hardware. UI preferences. You can't get a Mac 2 in 1 or a Mac foldable or a Mac gaming notebook or a Mac that weighs less than a kilogram. You can't get a Mac with an OLED screen or a numpad. Some people just prefer the Windows UI too. I usually use Linux but between MacOS and Windows, I prefer the latter.
We use the sales metrics and signals available to us.
I don't know what to say except resign to the fact that the world is fundamentally unfair, and you won't ever get to run the A/B experiment that you want. So yes, Windows it is !