Not good comparision between artistic products vs hard requirement software product.
- If your movie is running out of time, you slash scenes, production etc.
- If your bussines software dev is running out of time and does not meet the minimun requirement, you can NOT slash it. Specially if it mission critical.
In How Big Things Get Done the author Bent is an advocate of reference class forecasting, which is basically what OP describes.
Bent, who studies megaprojects, who goes on to say that the big mistake everyone makes when coming up with estimates is to think that their project is "special". People come up with a million reasons why their project is unique, and then they produce an incorrect estimate because they try to consider each facet of the project and add or subtract time based on it.
In contrast, reference class forcasting "bakes in" all the various factors and averages them. If you're trying to build a house and want to estimate how long it will take, take the average time it takes to build a house of similar square footage in your state. This will factor in things like risk of a storm causing delays or cost overruns, and you don't have to consider that or other unknown unknowns.
If you think some aspect is important, find a reference class that can index on that aspect. The estimate you produce will be more empirical and data driven that way.
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