Yes, in many markets it is fairly easy. But in most it is not. In fact, anywhere you are, it's quite a hassle to find a good tenant, find new ones when the previous occupier leaves, fix the house etc...
"Only" 5%? That's more than the average margin on owning real estate. Meaning, that 5% makes the difference between a profit and a loss on owning the building. 5% is a lot when you look at the cost of the capital that is required.
(as a side note, I'm hard pressed to believe that for 5% everything is included (taxes, fees, ...) and that they do everything for you for that money. I'd pay 9% here in Europe, including tax, and for that money they'd put ads in the papers/internet, show the building to tenants, check if payments are made and put a lawyer on it when they're not (but I'd still have to pay the lawyer) and take the phone when something needs fixing. I'd still have to find, send and pay a repairman myself).