[bobthepanda]

If anything, complexity probably increases exponentially as you have to consider ever more permutations of possible project.

[japaneseminisub]

I agree, and think that this should be incorporated into the cost.

Ie, a project twice as complex should be 5x the cost due to the additional management, comms overhead, permutations and potential risk.

Said another way the curve is logarithmic and there's a theoretical upper bound on project complexity.

[Retric]

Total project complexity isn’t the relevant metric here, a project with 100x the budget has more people managing it any many decisions don’t make it to the top.

Also, if a 2x as complex a thing takes 10x the budget then that scaling is already part of the budget figure.