I'm not sure how those statistics were compiled, but I'd imagine it's harder to collect information on therapists in private practice than it is to simply pool data from companies (e.g. community mental health agencies, state hospitals) who employ therapists. I could see those numbers being accurate if you're employed by someone, but if you're in private practice, you can definitely earn more.
Most insurance companies will reimburse licensed master's-level clinicians at $75 per session. Even if you only see 20 clients per week for 48 out of 52 weeks per year, that is a gross salary of $72,000. Now if you are business savvy and can get some clients to pay out-of-pocket, or clients who have a good PPO plan, you can charge your full fee (which is whatever you decide it is). This could probably push you over $80,000 gross per year. Even after overhead, continuing education, and health insurance, you are going to make out alright. You won't be rich, but you can live comfortably.
I know many master's-level therapists who supplement their clinical income with supervisory roles and adjunct teaching. It is not unheard of for therapists who work hard, take on multiple roles, and love/are good at what they do to break the $100,000 mark in annual income. It is not easy, but it can be achieved over time if you are diligent, passionate, and know how to network. Therapists who never bother to get licensed, settle into a community agency role, see their job as 'just a job', and don't bother much to get around the field outside of their place of employment, are A LOT less likely to reach these numbers.