Feels like the majority of those well-known failures (the 'we spent $5 billion+ and spent 10 years on something that should have taken a few years and maybe a tenth of that budget ones) come from either management who has no idea what they want, planning that hasn't taken into account even half the obstacles the project will need to overcome, or dozens of leaders all trying to make their mark.
Actual technical/work incompetence probably plays some part, but it's probably less of a matter of "people weren't honest enough about the quality of other people's work" and more of a matter of "we hired the cheapest possible team to do the work, and they weren't qualified in the slightest".
Bonus points for the leader of that team being the nephew/niece/relative of some guy in charge of the project.