I don't know if there used to be national Broadway advertisements, but I don't see why there would be now. In order to sell someone in, say, Middle America, tickets to go see
In the Heights (hell, let's go super-commercial and say
Young Frankenstein), you've also got to sell that person transportation and hotel costs, as well as ancillary costs of the stay in New York. I don't think enough people are willing to shell out that kind of money to make national advertising cost-effective.
"You mean what was the best picture of the year or what did they pick as the best picture of the year?" - California Suite