I’m getting pretty old so I have experienced multiple waterfall projects. The comic should be
You want to go to mars You spend 3 months designing a rocket You spend 6 months building a rocket You spend a month testing the rocket and notice there is a critical desing flaw.
You start over again with a new design and work on it for 2 months You spend another 6 months building it You spend 2 months testing
Rocket works fine now, but multiple other companies already have been to Mars, so no need to even go anymore.
Even with millennials (1981 to 1996) there is a big difference when you where born.
If you are an early millennial you grew up with MS-DOS, so you had to learn the terminal to get anything done. You probably had your first smartphone after you where 25.
If you are a late millennial you grew up with Windows XP and probably had a smartphone as a teen.