Theory about Robyn...

I never could make sense of Robyn when I originally saw the show. But this occurred to me on my second rewatch....

Robyn actually seems genuinely interested in the whole polygamy thing at the beginning, in my opinion. Yes, I think she secretly wanted special treatment and liked the perks of being the new, skinny, shiny wife. But I noticed a real change emerging in her when they moved to Vegas and before they could unpack their bags, she announces she's pregnant and gets the "disappointing" reaction from the family, especially the teens. This obviously bothered her a lot according to her talking head interviews, and I think this was the first time she convinced herself she was the VICTIM in the family and began nursing resentment about it. She then convinces the family to go in on MSWC and when the other wives begin to fade out on it because it's not their dream, again, she goes to the VICTIM mentality. More resentment is built. Instead of maturely accepting, she again feels they've abandoned her and goes to the POOR ME posture. (Don't even get me started on Meri wanting to go back to college and her self-centered reaction to the news.)

Later, when COVID hits I think she viewed her precious tenders as MORE at risk than the other kids (Sol's bout with RSV, etc) and so wasn't willing to "keep the family together" because her progeny's health might be jeopardized. That the other moms wouldn't lock down their kids and deprive them of a social life again took her to VICTIM mentality, and more resentment ensued. I think her resentment even fueled, at least in part, her passive aggressive insistence on/pressuring of Meri to stay well past the shelf life of the relationship with Kody.

After all this (and I'm sure there are other things I'm not remembering), I think she ended up with amassed, hardened resentment toward the OG3 and their kids (I'm thinking of the sign on the fridge about NOT taking food please and her not encouraging Kody to be a father and try to connect with his estranged kids/boys during Covid). Ultimately I think all this resentment caused her to evolve from her original stance of wanting polygamy to realizing that she could only have everything she wanted if she pushed the other wives away and kept Kody, her best customer, the happiest.

Just a theory, but there it is.

*Edited for spelling/grammar.

*Edited to add this: All the crying about the "I wanted to sit on a porch with my sister wives" was, as I see it, less about her mourning the dissolution of the family but instead more about her own self-pity that everybody else got in the way (/s) of her deluded dream.