PM intern vs full time

I was paid 80k as PM intern

Because they are ....interns? Yo what the hell is going on today.

Not offended :)

1. Market is like that. Full timers will not join the company if paid 10-20k, Interns will join.
2. Typically, there is an extended relationship value with a full timer and expectations that go across years, based on grooming, learning, application, decisioning, domain knowledge, interpersonal etc. Not an apple to apple with Interns.
3. If the graph of intern's value addition is a straight line with a 5 degree slope, the graph of a full timer's value addition is perceived to be a J or worst case a S curve.

Humour me, on a counter. Why should PM Interns be paid equal to full timers?