They do not deliver the product they claim to sell you. 

A lot of those older houses have corroded cast iron or galvanized pipes.Asbestos - This was use in many house products all the way back to the 30s.Lead-based paint - This was used up until 1977.  

I am focusing on trying to find off market deals and working with creative finance since expansion is slow moving based on my salary, and I'm too impatient to wait for the duplexes to earn another down payment.Is there a financing option that I am missing to get a loan for a down payment?

Slow and steady and safe is the best way to invest. 

@Mark Enis this is ENTIRELY dependent on the loan product you are using. 

But many people like having a feel for what's going on at their property, and find controlling their reputation and product is easier with small or mid-sized buildings.

I am a partner in a General Contracting business building new Custom and Production homes.

Although I have plenty of carry-over depreciation for now, if I decide to slow down in the future, it will help offset my taxes to a significant degree.

Regardless of the real estate type, I think it’s more productive to just make $600k a year in your job and get some great properties in great locations, enjoy the tax savings, and let time do its thing with appreciation and mortgage pay down.

But its seems like these products are imaginary programs that people have heard of but nobody has actually done one.