$40t in debt
In debt to whom?
It's something of a joke to talk about credit expansion in a closed economic loop. Especially when the loop tightens and you end up with...

If I owe you a million dollars and you owe me a million dollars dollars, are we collectively $2M in debt?
We're entirely too zeroed in on the fictitious credit balances and totally divorced from real material conditions. How many labor hours are we spending? How much of our fossil fuel energy reserve have we committed? What is the growth/contraction rate of potable water and arable land?
I don't really give a shit about $40T in IOUs. I care about the actual managed decline of the capital stock. The actual number of skilled laborers in a given profession. The long-term burn-down of natural resources relative to our ability to conserve, recycle, and reproduce them.