Back when I was in grad school, persons graduating from schools of law were awarded a bachelors degree. By the 1960s, most law schools required an undergraduate degree as an admission requirement, but many did not. By the early 70s law schools decided that their graduates should hold a doctorate. Graduates from previous years were awarded the doctorate ex post facto. It's still possible to become a lawyer in some states without going to law school at all, through an apprenticeship process. These people have a higher initial pass rate on bar exams.
The idea of awarding doctoral degrees to lawyers, physicians, dentists and various other practitioners and clinicians is mostly hype and marketing. Newly minted physical therapists are now awarded some sort of doctorate. Pharmacists, nurses, and real estate brokers are not far behind. The whole thing is kind of silly, like every little third-rate college transforming itself into a university.