As someone who has been hospitalized for an attempt I would absolutely disagree that lack of control was even a factor.

There is also a huge difference between a passing thought of suicide and being suicidal. Two vastly different experiences.

I can guarantee that taking control of something would not have changed anything for me. I require medication. I require therapy. I require support. I've also required hospitalization.

I cant speak for everyone, but for myself I disagree with your theory. It may work for some people, but honestly I think they would be in the minority.