The notion that governments have to eventually pay back debt is somewhat anachronistic. The United States has run deficits for decades, yet they are still seen as the world's reserve currency. The argument is that as long as governments can comfortably service existing and new debt, then that's all that matters as credit-worthiness is maintained.
The far end of the spectrum is Modern Monetary Theory, which is starting to gain traction in political circles:
https://www.vox.com/future-perfect/2...ment-explained