The 737 Max grounding cost about $18 billion so far (according tot he Google infobox which knows everything and is never wrong.) The high-end estimates of the value of a statistical human life tend to run about $4-8 million, depending who you ask. The FAA grounding of the Max has 2250 has thus cost enough money to save 2,250-4,500 statistical lives, had the money been spent more wisely elsewhere.

How does your "better" passenger-deaths-per-km measure account for these deaths? (And what is it superior to, exactly?)

You can't point to the grounding of the 737 Max 8 as a reliable indicator of the cost of regulation because:

1. Arguably this is the cost of regulations not being followed properly

2. This is an extra-ordinary circumstance that is costing much more than a regular plane would cost to get certified and fly (see point 1)

3. You are drastically underestimating the cost to the industry both in terms of reduced customer confidence, hull losses (~$100mil an airplane), and increased insurance premiums if we were to continue flying the Max 8.

But honestly, I'm having a really hard time understanding what your point is. Are you asserting that we should just fly the Max 8 and not worry about it? Are you asserting that airplanes aren't safer now? What are you getting at?

> (And what is it superior to, exactly?)

Pretty much any other form of transit, safety-wise.

https://en.wikipedia.org/wiki/Aviation_safety#United_States

> The number of deaths per passenger-mile on commercial airlines in the United States between 2000 and 2010 was about 0.2 deaths per 10 billion passenger-miles. For driving, the rate was 150 per 10 billion vehicle-miles for 2000 : 750 times higher per mile than for flying in a commercial airplane.

> How does your "better" passenger-deaths-per-km measure account for these deaths?

You propose a silly metric. Car accidents cost $871 billion a year. https://www.pbs.org/newshour/nation/motor-vehicle-crashes-u-...

just want to call out -

  The engine literally exploded, and they made it home via the rest of the plane OK (minus the unfortunate passenger).  

In the past this would have cut hydrolics (this happened with a DC10 rear engine exploding) and then losing control. Major props to the pilots and boeing (all SW planes are 737s I believe).

Yes, Southwest only flies 737s in order to simplify their maintenance logistics and to ensure that every pilot they have can fly every plane.