Compared to Starliner and its move from Atlas V to Vulcan [0], SLS is a paragon of incremental success. Additionally, to be fair to SLS, many of the problems associated with the program have to do with the mobile launch platform, which was built for the previous Constellation program and required considerable refit for SLS. [1]

0. https://arstechnica.com/science/2022/09/nasa-will-pay-boeing...

1. https://en.wikipedia.org/wiki/Exploration_Ground_Systems#Lau...