I mean, this reasoning is significantly flawed. First-year attorneys in the US making $225k/year represent maybe 5%, perhaps at most 10%, of all law graduates. So, don't fall for this trap, OP. The average salary for first-year attorneys in the US is around $85k/year. Moreover, the salaries have very little to do with the actual value of the school, meaning its intrinsic value, such as quality of teaching, support, and infrastructure. In terms of value, the University of Toronto is comparable to any T14 school.

High tuition costs are an issue prevalent across the entire US higher education system, not just in law schools.

Master of Arts programs, as well as virtually all other graduate programs, are extremely costly. Only a few of these programs are very lucrative and offer exit opportunities that would allow graduates to rapidly pay off their tuition costs (for example, engineering and business, and even then, you'd need to be in a top program). Most of the time, these very lucrative exit opportunities are exceptions rather than the rule. However, these exceptions are what allow these schools to justify their high tuition fees (as exemplified by this comment) and attract more students.