Their LP’s would probably take a hit to unlock the cash and get into something more likely to rebound faster.
The 787's and the A321LRs are good planes that they could sell, but the 737-800 is an obsolete plane which has a very hard time operating with a profit when competing against the new crop of fuel-efficient narrow bodies. You can't really sell them to anyone for any reasonable amount in the current market. MAX 8's are also hard to get rid off, but for a different reason.
Then the company they got loans from has a repayment deficit, they can repossess the leasing companies assets, and pay to store them, and try to sell them ... but they're going to be getting pennies-on-the-dollar (who wants to pay to store aeroplanes they can't fly for profit?). Duplicate that over the other loans they called in in other industries; now they're burning cash as well??
If the top of the tree, the banks or capitalists, can hold out then they stand to make a tidy packet when markets rebuoy but even then there'll be a huge lag if they laid off multiple tiers of companies.
Either we all have to agree not to force each other to close down, or we all do each other over. It's not pretty.
I'm wondering what happened in 1918 with "Spanish Flu", people instigated social distancing then - closing down schools and churches - so presumably there were businesses too that couldn't pay their rents? I imagine things were less severe because more businesses would own their resources, and would be part of communities that would collapse if they called in what they were owed.