Usury is so delicious to many that it’s unfathomable to consider any other incentive comparing to it

What is unfathomable is how you have a functioning economy without easy access to loans at reasonable interest rates.

Try reading Graeber/Wengrow

The same way Stock Market works. Really, Debt benefits a tiny fraction of people involved in the market.

Isn't it just the same thing? You loan the company money and in return they give you a note that says you get a portion of the company and dividends?

Different mechanics, but stripping everything away, roughly the same.