I read a story about this discussion last week by fund managers and strategists at the Reuters Global Investment Outlook 2020 Summit. The consensus of these people is that we will NOT see negative interest rates. Why? First, we have seen the negative effects of negative interest rates in Europe and Japan. Second, these "experts" said that the Fed under Powell wants to avoid negative interest rates.
Third, these "experts" believe we will see Quantitative Easing again during the next recession. Honestly, Quantitative Easing, if it includes long-term Treasuries and mortgage bonds, would be more beneficial for mortgage rates and housing markets.