Simply calling something a house-hack explains nothing (except that you're probably a millennial, JK).Also, selling your primary residence or any other property just to access cash for investing has multiple alternatives, including HELOC as mentioned above.

My theory is that millennial buyers are not inclined to want to landlord and, hence, the duplex market is weighted heavily toward investors who are too canny to overpay because of emotional response to a property.   

Many millennials don’t want to be tied to long-term leases and want the ability to move every few months to a new place.

Basically, to summarize, they say all the baby boomers properties will be going on the market in the next 10-20 years and most millennials will not yet be able to purchase giving a huge oversupply of empty houses.  

Especially with millennials starting to buy their first homes finally.

I ve been looking multifamily in the area and most of the things around 5% cap There is opportunity in Fort Lauderdale, the macroeconomics and job growth is stimulating in migration from millennials who are primarily renting, which opens the door for further growth in rental rates.

I'm not real familiar with that market but I wonder if properties that target millennial first time buyers would sell better. 

Additionally, the influx of millennials entering the home-buying market has created a strong demand for starter homes and entry-level properties.What do you think of the potential impact of remote work on the real estate market?

There's a plethora of Gen Zers and young Millennials that are living with mom & dad.

Big employers include The Limited (Victoria's Secret, Bath & Body), Nationwide Insurance HQ, Worthington Industries, Honda of America, State Farm, MANY others including a fast growing TEHNOLOGY hub that is attracting millennials, and Capital Unviersity, Ohio State, DeVry, Franklin University, Otterbein College, Columbus College of Art Design, PLUS medical OSU Hospital and James Cancer Center, Riverside Methodist Hospital, St.Anne's Hospital, Grant Hospital, etc.