I'd check your numbers on that from 30 years ago. They weren't even in the same universe of selectivity as they are now. Full-time/part-time is totally irrelevant. What, are you the most elitist credentialist of all time lol? Jesus.
Getting a Stanford MS while working was somewhat normal then (possible for mere mortals and not superhumans) if you worked at the right company, not really the same as getting into undergrad at all.