But paying off debt gives you security. The borrower is servant to the lender. If you have no debt you have freedom.
Sure, if you have a successful business and leverage debt for the business you will use other people's money to make you more money. Basic economics. But then again, if it goes belly-up, you won't just go broke and go back to zero, you'll go way into the negative and have a debt you have to work for years to repay - a friend of mine went farming some years ago on borrowed money, went broke, and worked for years after that to pay off his business debts. Debt is a high risk / high return proposition.
Most theoretical mathematical calculations around debt, like your own statement, assume the business proposal will actually work. If it works, you're right. But you can be very, very wrong also.