Most landlords bought the place earlier when home prices and mortgage rates were lower, or they just own the place outright and don’t make any mortgage payments.
This article is about choosing whether to buy at current rates or rent at current rates. If you bought a place 10 years ago for half the price it’s worth now and a 2% interest rate then you’re probably going to be paying less then renting
It’s just talking about the first month / year. Assuming that only inflation is effecting prices to keep things simple the price of renting goes up over time with inflation, while a mortgage stays constant dollar wise, and since a dollar is worth less over time the payment is less.
Combine this with building equity the net cost of owning a home goes down over time while renting goes up. The question is when do those two lines meet, eg. If you bought a home now how long would it take to be paying the same as renting. Maybe it’s 5 years, maybe 10 or 15 depends on the market, judging by the article it seems that period is getting longer as the starting point for a mortgage is really high and will take a while to recover.