It’s also why we have a nuptial agreement that puts some of these protections back in place. It explicitly talks about the value of the SAH spouse’s contributions.
But a lot of parents aren’t even aware of these threats. I’m willing to bet that those SAHP friends of yours are in this category. Check out the thread where the woman was asking about moving here from NJ (IIRC) and how shocked she was when BG informed her of some of the custody and other issues she might have to face if she moved to CA and subsequently got divorced.