And that is very true.

It's that at some point someone realized they could use their momentary surplus to exploit someone else's dire need and thus use other people's labor to generate an even larger surplus for themselves.

The rationale to justify this exploitation has changed through the ages, as well as how much has to be spent to coax others - going from slavery all the way to whatever is on the other end, which I guess would be the shared ownership of the means of production.