Well, the landlord pays more than that. You have to pay maintenance, property management (which you might do yourself), advertising, tenant screening, capital expenses (roof, sewer, etc.), evictions, vacancies, tenant damage, etc.
Still, that looks like a good deal.
Rent: $1500
All expenses: $750
NOI: $750
P&I: $466 ($70K, 30 years, 7%)
Cash flow: $284
Those numbers might work in some markets but not in mine. In markets where home values are higher and rents have not kept up it is impossible to experience that much cash flow.
Then you can't own rental properties there except as speculation. If you get some appreciation, enough to make up for your monthly losses, you'll make money. If appreciation is less, or, as is happening in many, many, many places, negative, you'll lose money each month and when you sell. The math could care less about your market. The math tells you whether its an investment (i.e., generates income each month) or speculation (requires appreciation to avoid losses.)