The market seems to have space for both top-shelf and the bottom-shelf (the $400/lb). 

So from the get go you may find that seller financing is a non starter if your properties are highly depreciated and secondarily appreciated.The 1031 exchange has a limited shelf life of 180 days. 

My ambition and drive is infinite, always has been and always will be.

I realize you can get infinite ROI with BRRRR, but I don't think that's what the big players do.

The benefit is in the ability to use the same pot of cash over and over again to scale up your portfolio quicker with Infinite CCR!

This makes ROI investment infinite and almost meaningless.

Even when a unit is old and dying and it would make infinitely more sense to replace. 

I looked at the place and believe that I can sublet it for $700, creating a  $40 cash flow with no money down (so technically infinite returns).

Shelf live over 10 years, and doesn't deteriorate like carpet over time (meaning it holds its rental appeal longer). 

If you find a great deal on a 4plex where you live in one unit and the other units provide you with total coverage and extra cash flow per month; then you CoC return is essentially infinite (assuming you got your closing costs covered by the seller).