Navigational guides and models only help in charted territory.
Do you mean, what if the economy never recovers?
Then the Fed’s actions will soften the blow. They will have decoupled the spectre of deflation from the underlying destruction. It certainly won’t have caused more harm than would have otherwise occurred.
That said, no democracy survives 30%+ unemployment for long.
I think the FEDs doing these injections will distort the price of money in such a way that risky activities would be seen as less risky, and so spirals into further illiquidity when something bad hits the fan (again), and the FEDs will need to inject again.
The businesses failing needs to happen. The capital losses needs to happen. Like a forest fire - new growth can't come if the old capital doesn't die (i.e., those controlling the old capital is constantly being protected from downsides, which this illiquidity represent).