From the article: All of the preparation is, inarguably, effective: Never has a recovered black box been so badly damaged that it yields no usable data.

That seems to me like they might be at a sufficient level of durability already.

I worded that poorly; durability in the sense of being resistant to attack by bad actors, not in the event of a crash.

> being resistant to attack by bad actors

The recorders already to work really well for the purpose they're designed for.

The "bad actor in cockpit" plus "unexplained disappearance" scenario, for which they're not designed, simply doesn't happen often enough to be worthwhile worrying about.

Short version: flight recorders aren't broken, they don't need "fixing"

Long version: imagine you were to propose a major redesign to your employer's systems to attempt to diagnose unaccountable failures which based on historical data happen 0.00000018% of the time[0], what would be the response?

[0] back of napkin maths based on https://news.ycombinator.com/item?id=36284912

Presumably because the incidence of pilot murder-suicide falls below the threshold and genuine accidents fall above it.

What’s the ratio like, 1:10000?