Who is incentivized to run projects in the way proposed? Why are teams continuing to do waterfall if its results are so undesirable?<p>For what it's worth, all the startups I've worked for conducted software projects with the "collaborative" design phase described. From what I understand, large tech companies and "non-software corporations" run projects in the "waterfall-esque" way. Why is that? Surely it can't be entirely meritless, or these companies would not exist for long.