I think the reason is precisely one you mentioned - people are far more comfortable with the internet than they used to be and more people than before are looking everywhere for yield.If you can find an apartment complex which makes sense financially I say buy it.

You have the money now you are looking for passive income and are in a position to re-chart your life.

That is precisely why people typically get better returns on a 4 plex than a duplex.

I guess it possible to turn this chart upside down and read it that way...

Yes any investor who knows what they're doing can pull that information up and create an excel sheet with a chart but do you really want to dig through all the sales in an area when you can have it provided to you.

This is precisely why I self-manage (despite being out of state). 

I know this a question that you can't answer precisely but what is a reasonable monthly income range to expect? 

Take the above interest rate chart and overlay it with Federal Debt and GDP.  

Ask questions early to gather info and add value to their precise pain points.4.

Then the rest is my profit and hustle.For accurate occupancy rates and rental rates / comps, look at the current listing calendars and rates and watch them, chart them.