They already have plenty of hardware makers building ARM laptops running Windows or planning to. Windows is still the dominant operating system outside mobile,

They already have plenty of hardware makers building ARM laptops running Windows or planning to. Windows is still the dominant operating system outside mobile, and mobile hasn't yet killed laptops and desktops despite perennial announcements of their demise. They have the resources to do all kinds of things they don't do for the same reason: why would they? What would they get out of it? Apple is nothing next to the smallest Windows OEM.