It's amazing the things that stop being a "must have" as soon as they have to spend more money.
"if you do not give this an ordered priority, I will resolve items as I see fit. Should we need to stop for one reason or another, there is no guarantee of which have been resolved".
Often times that is okay. I also tell them to always take the ones they're most uncertain about first. Better to front load hard problems and uncertainties.
Add more "must have" scope, and something else has to give.
Software projects are kind of like ovens-- if something cooks perfectly at 300 (temperature units), using 25 minutes and using 5 (money units), that does not mean it will cook perfectly at 600 temperature units using 12.5 minutes and 10 money units. Most likely it will burn.
Every part is necessary, but that doesn't mean that there isn't an ordering. Finding something that's easy to manufacture is pretty useless if it turns out later that it kills the patient. On the other hand, a drug that's safe and effective, but is difficult to manufacture is still a viable drug; worst case, you do what drug companies do all the time and charge obscene prices per dose until you figure out how to scale the process.
The overall tone of the program was “we basically have infinite money, just get it done and the government will pay us back”. So they had a fucking army of consultants to accelerate a process that normally takes 5+ years down to 6 months and they were building down multiple roadmaps just in case they hit a block on one of them.