Give me a break. You'd need a down payment of ~400K to have a mortgage low enough to barely break even at $15,000 in rent per year. None of his math makes sense.
Of course you would really rent a 500k property at something more like 2500 a month but even then you'd need a down payment near 200k to start making a profit.
500k property at 2.75% is $200k down gets you under 15k
(this is very similar to my current mortgage)
Now you're going to object that the interest rate isn't that anymore, which is irrelevant. There are numbers that will work which are simply an example to illustrate how depreciation works, and you just don't like the arbitrary scenario.
Mate who cares about rates from years ago. You aren't getting anything under 5 these days. Not to mention those rates are for primary residences, you get even worse rates for investment properties.
The point is if you have 200k to put into a rental property you are already wealthy way beyond an average American.