The article seems contradictory. Is it really estimating if you drop features you can't finish to ship by a deadline? Is a 16 month estimate worthwhile when yo

The article seems contradictory. Is it really estimating if you drop features you can't finish to ship by a deadline? Is a 16 month estimate worthwhile when you screw around for 12 months before getting serious and then getting it done? If the upshot is just to keep a conversation going with stakeholders and always be working on the most important functionality, isn't this mostly accomplished by 2 week sprints with a touch of externally set deadline pressure (e.g., WWDC)?