>>4352337Once again, look at the nikkor z 26mm. The optics do not go to the edge. It would, believe it or not, fit inside E mount.
Now think about the nikkor z 26mm's build. It focuses externally. It has no filter threads. It is not fully weather sealed. By the time you add the hood to mitigate the WR, although not the heavily focus breathing design, the soft edges at every aperture, noisy focus motor, and extreme vignette, it ceases to be a pancake, increasing in length by about 50% (slightly more with the clear filter that is necessary to protect the protruding focusing group). It is suddenly ~1.5" long, just like sony's muffin lenses.
Canon RF's 28mm has a similar issue with a fragile protruding focus group and heavy focus breathing. It's optically superior to the nikon, and also, does not actually exceed the dimensions of the lens mount and could theoretically fit in E mount.
Sony has never, to my knowledge, released an FE mount non-macro lens with protruding focusing groups except for the repackaged minolta lenses. Why has sony not released a pancake? Probably because given a reasonable R&D budget, they ran into all the same issues as every other manufacturer. External focusing.