If I were in your position of having enough money to buy something outright, I would be buying SO much more with financing!! Is there a reason you think buying everything outright is better than financing them and getting more?? I'm just thinking this way for simple math:
You have $500k. You spend it all on one 16 unit complex, after expenses you net $6500/mo
OR
You have $500k. You buy FIVE 16 unit complexes at $500k each with 20% down. After mortgage and expenses on all of them, you net approx $17,000/mo......
As for the risk aversion, I am just starting out and I wanted NOTHING to do with SFH. I thought they were a waste of my time and money. Although, I have a lot of real estate knowledge from growing up with a broker as a mother and a contractor as a father so... I was pretty ready to jump into the game head first with 2 duplexes right off the bat. It's been just enough for me. I'm staying busy, learning a lot, but not too crazy.