I recently read that "the rich" borrow against their wealth and live off the money from the loan on their capital, because it does not incur a tax penalty, whereas selling an asset does.
I could see this playing out well with rental properties, and being quite advantageous. As the value of the house and the rents go up, to reduce your taxed income from the rental, you refinance and have a higher mortgage payment while still being cash flow positive enough to live off. Meanwhile you are flush with cash from the refinance to invest again and keep repeating. Or you could live off it, do whatever with it.