It’s litter, pure and simple.

Plenty of wholesalers/flippers there:https://www.biggerpockets.com/forums/521/topics/54...In addition to that @Jeff Rappaport organizes an investor meetup that's purely for networking.

Yes, we could keeps millions, but at the size we are today, we are certainly not hurting to make a profit, so this is purely a business decision.  

This is often better, unless you enjoy property management.If your constraints are purely financial, aka you an qualify up to 6-12 units on your own.

When I speak with my potential investors,  one of the questions I ask is whether the money they set aside to invest are purely allocated for investing after they have put some funds aside for a rainy day.

I have found that duplexes rarely make sense as a pure investment property.

If it's purely a rental, plan on putting 25% down, and in general, 20% minimum down is usually best especially if your market prices are historically high. 

And I suggest you NEVER rent back a property to the seller, I know people do that, but it is "pure stupid".

If you buy one of those and live in it your down payment can be less than 20% needed for a pure rental.

More importantly, a lot of those numbers would then be pure speculation.