Want to know the reason you are not getting them?

top two reasons:1. they can usually command a higher price through a real estate brokerage. 

@Robert Fry any reason why you just couldn't buy it from them normally?  

Unless there is a really good likelihood that the property will through off cash flow, or another good reason to purchase I would not buy it. 

No duplex in this neighborhood has ever sold for over $800k, and that was a few years ago and was in an even better area of the neighborhood (off the main road, and surrounded by much nicer houses).The next day, we are alerted by the listing agent that they went forward with another offer without even giving us a call or a chance to compete.

Depending on your main goal it'll drive your movements.

If I just bought a home that's reasonably priced, maybe with something like "needs TLC" in the description, could that be profitable as a rental home, with the idea that homes typically appreciate, and I wouldn't have a mortgage?

A lot of reasonably priced multifamily homes in the city. 

Maybe they know it and will say: no one will ever rent that space because it is too small, or too far outside of main office market, or local jurisdiction has onerous business fees, etc.  

I found that my roommates took more precaution when asking for certain things and actually did take really great care of the property""They will likely be better behaved and take better care of the unit if they know""It is better to tell them now and hope that they take better care of the property"None of the above quotes are logical and can all be handled by simply telling your "fellow roommate(s)" that you do not want to be held liable for their damages.Challenge anyone to come up with a LOGICAL reason to let a tenant know you are the owner (this will be fun!)...