Earlier quoted context omitted.
Until you have to replace a roof, or a tenant destroys the house, or it just doesn't rent for a while and nobody notices a water pipe breaking. It's risky to own a lot of buildings, and worse the risks are correlated if they're all in the same place (there could be a flood or wildfire etc.) Commercial real estate is different because your tenants are (more) professional.
You get insurance to manage risk. You factor in roof repairs, vacancy rates when determining rent meanwhile your property value over the last 10 years in most places around the world have at least doubled and more. Doesn't mean the next 10 years will see that growth but if you believe your country/area's population will grow it is probably a good investment for now in the western world.
Like I said, you can tell it doesn't work because these businesses don't exist. There are essentially no landlords who own multiple single family homes. They do exist for multifamily and commercial.