Waterfall is missing the part where the customer realizes they didn’t actually want to go to Mars they just wanted to view it out of a telescope.

But now they can only travel to Mars and the telescope is out of the budget because you spent so much money on the rocket

2 years later: It’s now up to the lawyers to figure out if it’s the rocket that doesn’t meet agreed requirements or if it’s on the customer for not giving proper requirements.

Actual real world right now giant rockets include

• One that is being built under waterfall methodology. It has been being built for several years. That’s the Blue Origin New Glen heavy lift reusable rocket

• One that is being developed under an agile methodology, it flew as a subscale lander to test their engine and flight control, it has flown four full test flights, improving on each. That’s SpaceX’s Starship

We are yet to see either launch a payload to orbit

Or the funders get bored of waiting after ten years of “no Mars yet” and cancel the project, leaving you with a half finished rocket.

All the projects that have shittier outcomes in my experience is always waterfall. This is mainly because the stakeholders usually have this bright idea to be added in the middle of development that’s really need to be added at all costs and then got angry when the timeline got pushed because of their fucking request breaking a lot of shit.

At least scrum has a lead time of around 2 weeks so that when someone has a idea we can tell them we’ll add it to the backlog and hope they forgot about it during the next sprint planning.

This is what I came to the comment section for.

If like me you’re not a pro, it seems to literally just mean linear phases, so yeah, any nonlinearity would cause problems.