They are neither fully independent nor fully dependent. It falls somewhere in the middle. The same will apply, just in a slightly less dramatic effect.

But surely the engineers were who were inventing jets and rocket guidance systems and radar understood probabilities of independent events. The point, which the author almost misses completely, is that they dramatically overestimated how correlated the measurements were.

Beyond that, while there's no accounting for taste, I find it to be an appallingly bad article. It's poor man's Malcolm Gladwell.

Understanding the probabilities of independent events is a different thing than identifying them.

It is very common for engineering projects to encounter problems caused by an issue which was understood but was not identified. Most engineering failures fall into this category. Humans simply make mistakes.