Well, my experiences have been nothing like OP's. Both were PhDs, both worked long hours, both have accepted payment far below their full fees, and both were in private practice. One also had a full-time University administrative job. But I am not in an urban area, but rather a University town.

I think there are a few flaws in the logic here when comparing professions. OP, if you have a PhD and are working as a high school teacher, you are under employed. You may be paid at the highest discretionary level, but the ceiling is determined by the position, not who holds it. If you held a University post, your income would be far more comparable.

Not sure what altruism or "working hard" has to do with anything. Such qualitative distinctions are just as unrealistic to demand from therapists as from teachers or nurses or anyone else in a helping profession. Many show such qualities as a function of the personality that informed their choice of profession. But to determine comparative worth based on intention seems pointless (and impossible) to me. If any professional doesn't embody a value I require, I find one who does. But I accept that it's my preference I'm serving, not a failing in the professional.

Any professional who is self-employed has business expenses; insurance reimbursements rarely match full fee. And some insurance agreements will not allow for any discretion in fee. In my experience, no professional I have hired has ever cost me more than lawyers. What we really need is insurance coverage for legal fees.