Probably paying $3k in rent for each of those apartments, $300 in utilities and cable, $800 in cleaning/laundry/expendables, plus probably budgeting $100/month

Probably paying $3k in rent for each of those apartments, $300 in utilities and cable, $800 in cleaning/laundry/expendables, plus probably budgeting $100/month to cover the faster than average wear and tear. So $109k/year in profits pre-tax. You could live on it, but you wouldn't exactly be rich.