How do we explain the growing gap between the return on equity and the long-term interest rate on government bonds?

In OECD countries there is a growing gap between companies’ return on equity and government bond yields. At equilibrium, this gap can only be due to: The fact that the risk premium that affects corporate assets has risen relative to the sovereign risk premium; this may be because investor demand for government bonds is strong or because central banks are expected to ensure government solvency; The lack of effect from the increase in the public debt on the sovereign risk premium : while the increase in corporate debt is driving up the corporate risk premium, even highly indebted governments are supposed to able to remain solvent. The skewing of income distribution at the expense of employees obviously drives up the return on equity, but if the corporate risk premium did not rise, it would also drive up the interest rate on public debt.