The debt is too high to repay. Servicing the debt is going to come home to roost soon. I recall a friend who spent himself into a hole and was only able to pay the interest. You can write the rest of the story.
This is it - they can't afford even the interest part of the debt any more. This is why they are so keen to devalue the currency, because they also devalue the debt.
But it doesn't work because economics 101.
This is how every world power has gone down - the currency is devalued and the power collapses.
Keynesian bullshit economics.
If you want a really good insight into economics and how we got to where we are, this is essential viewing: