What is the balance of power between governments and investors in public debt?

OECD governments currently have the power in the relationship between governments and investors. This is because demand for risk-free bonds is very strong, given the increase in global private savings and the regulations of financial intermediaries, and this demand is rationed by central bank purchases, which enables governments to place a very high amount of debt at very low interest rates. The question is therefore whether the balance of power between OECD governments and investors could switch to public debt investors in the future, which would drive up long-term interest rates sharply. Such a shift in the balance of power would result from: Central banks stopping their debt purchases; Population ageing, which would push down the savings rate; Changes in the regulations of financial intermediaries, eliminating financial repression and enabling them to buy far more risky assets.