Perhaps too simplistic since tenure is not the only way to “make it” in academia. Many people have academic careers without making tenure. You’ve also excluded people who publish impactful work, spend time teaching, and leave before seeking tenure. It might be fair to say 84% of graduating PhDs don’t make tenure, it’s just jumping to conclusions to say they don’t make it in academia.

Also don’t forget there’s a large time lag between graduating PhDs and when they get tenure, so today’s 270k graduates might be shooting for the next decade’s 15k or 20k tenure spots. Or… who knows they might be shooting for the future 5k spots if the rumors about colleges trying to reduce their use of tenure are true.

“Non-tenure-track faculty account for about half of all faculty appointments in American higher education.” … “About 90 percent of all full-time lecturers and nearly 50 percent of all full-time instructors are nontenure track.” https://www.aaup.org/report/status-non-tenure-track-faculty