Well, they just had a failure, so that spells great success, right?

I'm unclear on the point of why having a rocket blow up when you're being slow and careful is more of a setback than having one blow up when you aren't.

Information theory. If you are doing lots of small, incremental tests, burning through a lot of hardware doing all sorts of characterization and qualifying tests, learning a little bit from each one, you can make steady progress, finding your mistakes as you go.

If instead you try to work out everything in painstaking detail, build a small number of prototypes that your calculations assure you should work, and one blow sup, you learn that...your calculations are wrong.

Imagine developing software with no CI tests, where you only get to run one full system test every couple of months. Slow and careful means avoiding lots and lots of early learning opportunities.

Necessary and sufficient are different concepts.