Run Stable Diffusion on Intel CPUs
then - how far away are we from having it on M1/M2 Macs, at least with regular processing?
openvino may be one path I suppose: 
<a href="https://github.com/openvinotoolkit/openvino/issues/11554" rel="nofollow">https://github.com/openvinotoolkit/openvino/issues/11554</a>