Criminal lawyers advertise because they lack repeat business

Evidence

But a criminal lawyer had no retainer business, and few repeats. Word of mouth was one of the few ways he could build a practice. A criminal lawyer, unlike the Wall Street lawyer, wanted publicity, wanted his name in the paper. It was for this reason that these lawyers (to this day) like to call attention to themselves. Flamboyance was good for business. It was publicize or die. The good gray lawyers of Wall Street would starve if they had a criminal practice. — Lawrence M. Friedman, A History of American Law, 3255

Categorization

• CANDY: Nice compact, tweetable economic insight: no retainer business means criminal lawyers publicize or die, unlike Wall Street Gray lawyers.