Most people use computers to Get Stuff Done(tm).
Windows RT can't run Win32 and ARM can't run x86, at least not without significant caveats; people can't use Windows computers like that to Get Stuff Done(tm).
M* Apple on the other hand can run most x86 era MacOS software; people who were using Intel Macs to Get Stuff Done(tm) can use newer M* Apple Macs to Get Stuff Done(tm).
Computers are tools, their sole purpose is to enable their users to Get Stuff Done(tm). It is the natural order of the universe that Windows ARM computers, unable to Get Stuff Done(tm), completely and properly failed to capture market share.