For 2 bedrooms in my market, there are a lot available, however, most are in the undesirable part of town. 

Normal life changes for family units still apply, but vacancy is less than 10% and due to waiting lists, quickly rented if new vouchers are authorized.It's the landlord's responsibility to screen tenants, you can certainly have quality tenants in Sec 8, if you preceive this group as being undesirable, it's not the socio-economic factor as much as the lack of due diligence by the owner/manager.

If the area is in a geographically undesireable area or blighted neighborhood that is slowly declining which many communities in the Country are it may not be a very good investment.

I do not plan to live in any of my units - I have a family, dog, house that makes that option very undesirable to me.

Stocks have all taken a pounding and who knows how much lower it's going to go.

You might find available services don't meet your needs, or have undesirable terms.

Just find the most crime ridden,  undesirable area with frigid storms in the winter and mosquitos the size of small birds in the summer and invest there. 

The wifi would also have to be installed in the basement, which can only be accessed through one of the tenants units, so wifi is also undesirable. 

There are still some travel agents around even with the likes of Expedia and Kayak, so no, real estate agents won't become obsolete, and I think real estate agents can provide more value in the future than travel agents can because a home purchase is a much bigger deal than a trip and people don't want to be penny-wise and pound-foolish (for the most part).

Over the next 15+ years their value went from 20 thousand pounds per until to 125 pounds per unit.