The primary thing when you take a sword in your hands is your intention to cut the enemy, whatever the means. Whenever you parry, hit, spring, strike or touch the enemy’s cutting sword, you must cut the enemy in the same movement. It is essential to attain this. If you think only of hitting, springing, striking or touching the enemy, you will not be able actually to cut him.
The McNamara fallacy, named for Robert McNamara, the US Secretary of Defense from 1961 to 1968, involves making a decision based solely on quantitative observations (or metrics) and ignoring all others. The reason given is often that these other observations cannot be proven.
The fallacy refers to McNamara's belief as to what led the United States to defeat in the Vietnam War—specifically, his quantification of success in the war (e.g., in terms of enemy body count), ignoring other variables.
I want you to consider instead the possibility that Waterfall came to exist, and continues to exist, for the convenience of managers: people whose methods are inherited from military and civil engineering, and who, more than anything else, need you to promise them something specific, and then deliver exactly what you promised them, when you promised you’d deliver it. There exists many a corner office whose occupant, if forced to choose, will take an absence of surprises over a substantive outcome.
Features don’t work, in the sense that they can be easily gamed. A brittle and perfunctory implementation, done quickly, is going to score more intramural brownie points over a robust and complete one. If the question is "does product A have feature X?" then the answer is yes either way.
We use the term feature factory as a pejorative to designate companies addicted to adding features, while accumulating incalculable so-called technical debt. This situation is driven by management for the convenience of marketing, and I am skeptical that a more faithful application of Agile principles will correct it. Indeed, I suspect Agile processes are constitutionally vulnerable to this kind of compromise.
The presence of a feature can only indicate to a user if a goal is possible, behavior will determine how painful it will be to achieve it.