Perhaps, but the monetization would have to be pretty extreme. And that would send interest rates to the moon, making further borrowing difficult.

While these things are impossible to predict, my guess is that in a couple decades the government will do some sort of technical default. Force Treasury bond holders to exchange their current holdings at par for new bonds with longer maturities and artificially low interest rates. Politicians will be able to claim that no one has lost money since the nominal bond values will remain the same even though the market values will be much lower.

The other thing I expect to happen is that the government will force retirement accounts (both defined benefit pension plans and defined contribution 401k plans) to purchase Treasury bonds. Because of course they're so much "safer" for retirees than risky stocks.