Perhaps they should just be allowed to fail, but it's far from risk-free, especially when we're diving into a deep Depression the likes of which none of us have ever seen.
Some of the costs that you describe, like folks being less willing to invest in and work on things that have proven themselves to be unprofitable, may actually be benefits.
If the the whole market looked like this in the next year, people's 401k accounts would probably be demolished.
How many people do you know that truly had their lives ruined by the 2008 crash? Allowing the markets to find a bottom and recover creates opportunities for social mobility.
The people who don't want asset prices to drop are rich people. They are the ones who own the assets.
Also, beneficiaries of bankruptcies are the same billionaires and hedge funds being bailed out now. Distressed private equity funds will be salivating over all the fire sales.
Allowing companies (even ones that are large and considered important like airlines) to "fail" just means that they'd have to go through bankruptcy proceedings and that the owners would lose some money - it doesn't mean that their operations will shutter, or that the planes will suddenly disappear, or that everyone in those companies will suddenly be out of work.
There are many examples of how this works - a recent one being PG&E in California, who filed for bankruptcy last year. Our electricity is still running and the linemen are still working.