[proaralyst]

I just don't think agile is designed for fixed-anything. Every project has unknowns: you can either spend effort to de-risk the project and increase your confidence in the time/cost estimates, then sell the job (ie waterfall/big plan first); or you can Just Try Stuff and adapt as you figure out that various things are easier or harder than you thought.

I think consultancies and corporations looked at vertically-integrated tech companies having lots of success with agile & decided they needed agile themselves, but didn't want to give up fixed-price. Probably correctly! But the key to those tech companies' success was the vertical integration, not the agile methodology