Earlier quoted context omitted.
>This just indicates a failure to perform a proper Analysis/Specification/Requirements phase, with relevant qualifications steps. It doesn't matter if you're a Manager or a lowly Developer - if you can't adequately qualify the requirements and specifications, the analysis is simply not complete. But that view of requirements is not borne out by the reality for most projects. You're presuming that it's possible to gat…
If you can't formulate actionable requirements, you're either not the domain expert, or not communicating properly with the domain expert. What your service looks like now and what it looks like in five years are obviously two different questions, but a proper analysis will divide the issue between now and 5 years from now and come up with requirements that fill the gaps. This doesn't mean things get set in stone and…
The issue with the Waterfall model is that this approach doesn't work. Aiming for "now" means you come out with an outdated product in the future. Aiming for "5 years from now" means speculating on what users will eventually want, which is very error-prone. Trying to adjust course midway through is a nightmare - and completely defeats the point of trying to get requirements "right" the first time.
>You can of course empirically interact, by wearing the user hat.
This is not empirical: it does not involve observation or measurement of the real world. Speculating about user behaviour is no substitute for concrete data about how users actually behave.