Describing it as debt makes it sound like people tallied it, which I believe they didn’t for a long time. It gets the facts right but uses a very modern way to frame it. I think it’s more accurate to look at it as reciprocal altruism. I do you favors, you do OP favors, OP does me favors and we do so so long as it feels like nobody is mooching.
It’s the difference between 1) going out to a bar with friends and remembering “Alice has bought the group X rounds, Bob has bought Y rounds, and I’ve bought Z, meaning it’s Bob’s turn to buy a round because he is in beer debt” and 2) “Alice and Bob and I generally buy each other rounds and it all feels roughly balanced so I’ll buy this round.” Tracked and tallied debt came much later as I understand it.
It’s the difference between 1) going out to a bar with friends and remembering “Alice has bought the group X rounds, Bob has bought Y rounds, and I’ve bought Z, meaning it’s Bob’s turn to buy a round because he is in beer debt” and 2) “Alice and Bob and I generally buy each other rounds and it all feels roughly balanced so I’ll buy this round.” Tracked and tallied debt came much later as I understand it.