I get the feeling she only does shoots that fit in with the image she's trying to sell - and currently that's the effortless, sensual, earth mother who always has a smile on her face. She's happy to appear in fashion magazines, but her focus is on a more generic form of stardom.
She's like the Cindy Crawford of plus-sized modelling, where high fashion and her don't get along that well - but that's OK, because there are bigger prizes to be had.
And she's probably got a lot of rather boring avenues to explore and exhaust (body positivity, having a baby, health and fitness for a different body) before she has to resort to doing anything dramatic with her image. Maybe we'll get some spicy shoots to remind us that "mothers can be sexy too!!!"