In great light, SFP is no problem, because you can still see at maximum magnification. If you need to turn magnification down to brighten it up, an SFP reticle becomes useless. Since SHTF is probably going to result in less than optimal lighting, I’d think we would want to prioritize usability in less than optimal lighting.
Now, this demands a good FFP reticle that works at less than maximum zoom, but March at the very least has figured out some workable techniques.
According to ILya, who’s probably forgotten more about optics than most of the people on this site combined have ever known, it is very very difficult to make a true 1x LVPO with the larger lens you’d need to keep a good exit pupil at high zoom, and by necessity results in a large and heavy optic.