Of course, not all debt is BAD debt & since they are only ever focused on buying companies, they don't understand GOOD debt at all.
Every month he would watch his net worth rise as others paid off the interest (owed to the bank) as well as paid down his principal, thus increasing his net worth.
That's why we call it GOOD.
• if the property market moved up, his properties would be worth more
• if he rehabbed his properties, he would "force appreciate" them higher, even if the market didn't move up
• because a property has the greatest tax advantages, he was able to write off (some) personal expenses against his asset income
• in other countries, investors can even write off mortgage interest as an expense & in special cases (like AU) write off rental losses against personal income