That been said, if your return is not substantial, it's probably not worth your time and money (and some aggravation).2. 

Feel free to charge for aggravation.   

The very aggravating part is that I never hear back from the person.

Ultimately, this is not worth the time nor aggravation to pursue.  

I bought our current home, a duplex, as a house hack/investment, by way of my own decision without her input and she is still aggravated about it almost 5 years later.

As someone new looking to get started and hopefully set myself up for retirement in ~15 years, is that enough time or should I just put all my money in a brokerage account and save myself a lot of aggravation ? 

The is too much professional time and billings, zoom calls, aggravation.  

To aggravated the matters even more, in the rare case whereby a buyer finds a fsbo on Zillow, the lising points the potential buyer to a realtor – owner’s contact information is completely obscured while a realtor’s info is as highlighted as possible at the very top of the page, so concomitantly and in a subliminal way the page containing the fsbo listing implies to the potential buyer that he/she needs a realtor.

And for us, we would rather take a financial hit and have to fix plumbing than to have intact plumbing, but a tub full of bowel movements...the gross is worse for us!

That's a guaranteed return without the aggravation of being a landlord.