I'm inclined to give Chiney some benefit of the doubt here, because she knows her injury situation better than we do, and I suspect she may know that her WNBA shelf life is <5 years, and maybe even just a year or two. She's said in some recent podcast interviews that she wants to go to law school, and I suspect she picked Stanford not just to follow her older sister but because she cared about "the 40-year decision." She traded likely championships at UConn for the Stanford experience, network and doors that open with it. She's killing it on ESPN and it's palpable that she has big plans after she hangs up her sneakers.
In LA, she has far more ability to explore post-basketball opportunities in media, sports, and entertainment. She could enroll part-time in law school and live in L.A. year-round. She could try to be a regular commentator for Clippers or Lakers games. Etc. The reality is that Uncasville, CT has 1/100th the non-basketball opportunities L.A. does, and if she only has a few seasons left, why shouldn't she play them out with her sister, maybe win a championship in the process, and get her post-basketball life in order?
I totally understand why that sucks for the Sun, and it's true that they were very good to her in 2015, but since then her injury situation has likely reduced her basketball shelf life, and her extra-curricular activities are probably much more attractive than they seemed four years ago. I suspect she just made another 40-year decision...