In the next couple of months I'll be leaving my factory job to start a painting business.

Haven't you ever seen new cars being shipped from the factory to the dealership on car carriers?

Not that carpet is mass produced in a factory and labor for wood floors is so high, it has reversed.

One factor is that many of the typical Baltimore row houses are small and not that appealing architecturally.  

BTW, this is pretty much how I built a Real Estate Portfolio that is worth around $20 Million today, generating almost $1 Million in Rental Revenues and Cash Flows for the Partners very significantly.HOWEVER, as I have been saying, calculations cannot be the only factor. I

Another factor I had growing up is the hand-to-mouth existence of farmers in what is now the Rust Belt, but back in the 1960s, the area where I was living was decreed to be an economic disaster zone by the Johnson Administration.

(even if factory treatment seems pretty good these days)

And here is the "price" we all must pay for unlimited cheap labor over the last 40 years; instead of factories producing, green, long lasting, efficient, modular housing that would probably cost about as much as a honda accord, we are stuck with a perception that site built is better, preferable, the only attractive option, because we have been able to take advantage of immigrant workers to create an unsustainable system that does not value the cost efficiencies granted every other mass produced product.

Investing in buy and hold real estate really doesn't take a lot of time at first and I think most here would agree the biggest limiting factor is access to capital and credit. 

The depreciation factor is extremely obvious, just take a peek at a crime map once in a while.