He and those that adopted it were very fortunate to say the least, but there are numerous others in the past that have not been.  

We have no maintenance to worry about where we live and generally live much more comfortably than if we lived in a building that we were responsible for.Also there are numerous tax deductions available for rental property that ARE NOT available for owner occupied units.Don’t wait to buy real estate.

I have originated numerous BRRRR loans over the years and work with people across the country that attempt to do them, both successfully and unsuccessfully, and most are misguided on how to do it right, IMO.

Besides the improved cash flow from one asset, another of the benefits you'll find is that managing one property in one location is a lot easier than managing numerous SFH properties in various geographic locations. 

I hear of more absentee owners complaining of the numerous calls and letters.

For a smallish development like u mentioned you could always use a local rolled metal supplier for the shell (3' metal for walls and ceiling) like michael mentioned and then just source the doors from one of the above suppliers after you know all your rough opening sizes on your doors.  

Some custodians will invest your cash into a variety of CDs at numerous banks so they can increase the float that they make on the money.

After that first experience, I personally took the evaluation process into my own hands and filtered through numerous prospective tenants until finally finding the one who met my both the paperwork standards as well as my gut feel. 

Also some building materials suppliers offer financing to their builders for specs.

Property values are constantly increasing due to numerous business opportunities in the area.