But back then, in the haze of the Vietnam era, investment banking, and business in general was not greatly
admired. These days, it seems more liberal arts college students are interested in fields such as investment banking, consulting and hot-shot computer science. Some schools have better access o those highly-competitive careers than others. More are universities, some are LACs.
It seems reasonable to me that feasibility of entry to such high-remuneration fields, and just jobs period, may impact proportional entry to PhD programs at those schools where this is a factor. And where jobs are not so available, the converse may be true to an extent. I am familiar with one LAC where the biggest on-campus recruiter was the Peace Corps. Others apparently have plenty of recruiting.