Residential at least has a chance of being profitable. 

I find that cash flow is very important so that I don’t have to come “out of pocket” to pay for major improvements / repairs  

The chances of this situation happening are not high but it does happen.

I never paint, swap rugs (except flooding), or do other improvements on rent controlled units This can lead to blight.Who benefits from rent control?

Say you paid 100k 6 years ago and have done nothing to improve the property value.

Not a chance.  

This would give us a chance to buy a house, funded through Lee Arnold’s company, which would be rehabbed by Lee Arnold’s contractors in a completely turnkey operation.

Smart investors first focus on finding quality properties—such as those in thriving areas of Brooklyn or potential neighborhoods around Manhattan—and then reverse engineer the process by improving management, optimizing rental structures, or enhancing facilities to make it worthwhile.

I was in your spot at 23, took a chance, and started a business.

These systems are becoming more sophisticated and (my favorite) capable, leading to improved user experiences and potentially freeing up human employees to handle more complex tasks and interactions.