Nobody wanted Arm-based Windows devices. The early RT devices had terrible performance and failed to compete in any meaningful way, had terrible compatibility and no (?) emulation, and since the products were mostly terrible, Microsoft never supported them well, nor pushed for a developer transition, and consequently they got abandoned quickly. The few newer devices out there, like the Surface Pro X, still don't perform competitively, cost way too much for what they are, often aren't straightforward, standard laptops, have emulation issues, and have Intel alternatives.

For a transition like this, you need good products, you need good emulation, and you double-plus-emphasis need to commit. Windows cannot do that.