I practiced law for almost 40 years so I know what you mean. But I took at least 1 pro bono case a year while I was in private practice. Sometimes 2 if my partners would let me. High profile cases brought in more clients. There are other ways to be reimbursed for expenses.
My fees were low enough that low-income single mothers could afford me for their paternity & child support cases. In any event, Lisa Cook doesn't need a pro bono lawyer. en.wikipedia.org/wiki/Lisa_Cook Hopefully, the court will order the defendant to pay her legal fees and expenses.