An exodus appears to be under way of Ph.D.s and faculty generally, who are leaving academia in the face of political, financial and enrollment crises. It’s a trend federal data and other sources show began even before Trump returned to the White House. On top of everything else affecting higher education, this is likely to reduce the quality of education for undergraduates, experts say. Nearly 70 percent of people receiving doctorates were already leaving higher education for industry, government and other sectors, not including those without job offers or who opted to continue their studies, according to the most recent available figures from the National Science Foundation — up from fewer than 50 percent decades ago.