Really? So I purchase a $100,000 house for 20% down at $3.5% interest, live in it for 30 years, during which time the loan is completely paid off and the house goes up 5-fold in value, I profit $400,000, minus about $53,000 in total interest (plus the tax savings on the interest).
Or, I use the $80,000 that I would have used to pay down the loan to instead purchase four other $100,000 houses (five in total), and get 3.5% interest-only loans which I pay for 30 years. I live in one of the houses and rent out the other four at a positive cash flow. I sell each of the houses for at $400,000 profit ($2,000,000 total profit), minus $525,000 interest (all tax deductible), plus my positive cash flow on the rent, plus about $150,000 of depreciation over 30 years, minus the $150,000 of recaptured depreciation when I sell the the rental houses.
Which scenario do you think represents the greater economic position?