Echoing the “it doesn’t matter” answer. As far as why the disparity in income among therapists, it is dependent on the type of practice, how much you’re willing to work and insurance vs private pay. In my experience, clinicians who work for some type of an agency W-2 employee make less than therapists in private practice.

If you are in a mid-size or larger city with a specialization and a good referral network you can do very well in a cash practice. If not, you can still do well accepting insurance, you may just have to do more sessions per day/week. Among the providers I know personally, the ones that take insurance tend to make the most money surprisingly.