The figures for the mortgage versus renting are bogus in any case. The writer has not compared like to like. An apartment with people walking around above you is not the same as a HOUSE. It is therefore no wonder the rent is 2.5 times cheaper than the mortgage.. it's on a property that's subjectively at least 2.5 times worse. Like for like, the mortgage on a similar apartment would be a lot less than $2500 a month.
Given increasing population, rents and property prices are unlikely to rise at just 0.4% above inflation over the next 30 years. While the mortgage payment can only go up based on interest rates (and it's not /that/ hard to lock into a fixed rate right now..), the rent will go up in absolute terms. Assuming a 3% rise after inflation, the unlucky renter will be paying $2303 per month at year 30, and very little will have been put into savings for the last 10 years. Worse, they won't have an asset - the homeowner will.
Buying a property with a mortgage gives you incredible leverage you'd struggle to obtain with other investments. The bank won't loan you $400,000 to invest in stock, but you can invest in a property this way.
Given that rising rents will cause the renter to barely be saving anything by year 20, that the renter will have no property and a less than exciting savings account come year 31, and that the renter has had to put up with all sorts of restrictions that come with rental properties (no modifications, often no pets, no guarantee you can stay there), I think the homeowner is a lot more wise if they plan on staying put for at least a few years.
Renting is a nightmare even if it proves to be cheaper in the /short-term/. If you're an automaton that doesn't mind uprooting whenever your landlords say so, perhaps it'll work for you. But for those of us with kids, pets and geographical attachments, owning a home gives us both an asset we're invested in using the bank's money for leverage, and a permanent base that only severe economic conditions can take away from us.