Crazy that she chose to renew with SM after all the suffering she's gone through. I think she's afraid to try something new, personally. It's par for the course when you're as introverted as she is, I'm the same way so I can relate but where I have a certain stubborness that pushes me forward Taeyeon seems more like the self-sacrificing type.
I worry about her sometimes, while she has seen happier recently there's been many times where I feel as if she's given up, times where the depression have been obvious and she immerses herself in so much work that she doesn't have to think.
It's not all SMs fault but I don't think they're helping, most senior idols (including her former members) seem so much happier after transfering to a smaller company with more freedom, but maybe that's the problem - freedom means less work and more time with herself.