The performance issues weren't locked in by their exclusive deal with Qualcomm?
I mean, sure there were other issues, they can call it "Windows" all they like, just like switching mac from PPC to Intel to ARM is still MacOS/OSX. Even if not everything is 100% compatible over time. That they made other dumb decisions doesn't make it less so.
Much like ARM on Linux doesn't run everything out of the box, doesn't make it not Linux.
They made the marketing blunder of calling the ARM OS "windows" when it couldn't run existing software. It's borderline fraud. Many people, (probably most) returned their RT devices to the store because of this.
Windows ARM laptops were more expensive, slower, & under-speced than x86 ones.
Microsoft restricted software download to store only - pretty dumb to me.
x86 Emulation was eventually released after win10 arm was released but it was slow and probably wasn't reliable.
Summary, high price but low performance, dumb os restrictions, & non existent ecosystem killed ms ARM efforts.