The author seems like he either knows nothing about real estate or, as you said, has other motives that aren't clear. He completely ignores the effect of mortg

The author seems like he either knows nothing about real estate or, as you said, has other motives that aren't clear. He completely ignores the effect of mortgages (leverage) and the expense of renting instead of buying. He ignores investment property (as you highlighted), the ROI of building on vacant land, tax advantages of owning, and numerous other factors.