Right now the four bed house next door to me in San Francisco is empty, and has been empty for the past three years - it's worth $4 million, and is owned by a family based in mainland China. On one occasion a representative of theirs stopped me in the street and asked if my home was for sale (fortunately for me my landlord decided it wasn't).
And when I lived in London I saw equally empty properties - new build flats worth millions of pounds completely deserted.
> A home lying empty has a negative return (due to maintenance and operating costs, still have to water lawns, repair weather damage, etc).
Not if the value of the home increases greater than the negative pressures...which it very much has been in many cities.
> A home being rented has a higher return. There is simply no reason from an investors perspective to leave a home empty unless you can't find a renter who will cover their costs
Tenants have their own problems. They have rights, homes are harder to liquidate with a tenant in, and you may decide it's just not worth the hassle. If you're expecting the property value to increase 50% over the next few years the income a tenant would be providing you is a relative pittance.