Part of the reason, I think, is that Qualcomm and Apple cut their teeth on mobile devices, and yeah wider SIMD is not at all a concern there. It's also possible they haven't even licensed SVE from Arm Holdings and don't really want to spend the money on it.

In Apple's case, they have both the GPU and the NPU to fall back on, and a more closed/controlled ecosystem that breaks backwards compatibility every few years anyway. But Qualcomm is not so lucky; Windows is far more open and far more backwards compatible. I think the bet is that there are enough users who don't need/care about that, but I would question why they would even want Windows in the first place, when macOS, ChromeOS, or even GNU/Linux are available.