Hmm, in my opinion, not great examples of how rockets aren't difficult anymore. Read recently that for Vulcan, ULA reused a lot of existing systems from Atlas V

Hmm, in my opinion, not great examples of how rockets aren't difficult anymore. Read recently that for Vulcan, ULA reused a lot of existing systems from Atlas V (such as the entire second stage, but also many other system) which obviously have been developed and used in actual flights for decades: https://spacenews.com/ula-to-fly-vulcan-technology-on-atlas-5-to-gain-flight-heritage/ https://spacenews.com/ula-to-fly-vulcan-technology-on-atlas-... And SLS reused old-tech even more so (at least from my understanding). For SLS, NASA used the boosters from the space shuttle for the first stage: https://www.nasa.gov/reference/space-launch-system-solid-rocket-booster/ https://www.nasa.gov/reference/space-launch-system-solid-roc... Yeah, NASA and ULA take the most conservative approach to rockets, using technology that they developed decades ago. ... but maybe that's what you mean by "following the established component and integration test playbook." It's smart and safe, but still, this also means they aren't innovating and, as you know, even for Space X, doing something new took them many, many years of failures, for Falcon 1, Falcon 9, and on into Starship.