The mandate from above is clear, just get it done! Avoid everything that's in the way: all advice, all expertise, all discovery efforts that detract from hitting the Date™!
What these organizations don't realize is that all software change can be modeled as three components: Value, Filler and Chaos. Chaos destroys Value and Filler is just functionality that nobody wants. When date pressure is applied to software projects, the work needed to remove Chaos is subtly placed on the chopping block. Work like error handling, clear logging, chaos & load testing and other quality work is quietly deferred in favor of hitting the Date™.
Finding value is the result of enabling individual and group-level discovery attempts. It's not the result of everyone following one leader's gut.
What just happened is a new software product/feature was created that no customer wanted. This happens way too often. In fact, most hyper important software projects that must be done by date certain or else, have deep flaws that cause some variation of this phenomenon, flaws that include:
Not wanted - Company specified a solution to a problem that customers don't actually have
No Rarity - Company is pursuing an iKnockoff of existing products. The market already has two scaled competitors with working solutions, customers naturally spend budget on products that are already successful to avoid risk
Incorrect Packaging - Customers need a website, but the company created an iOS app instead
Incorrect Pricing - Customers need SaaS pricing, but the company created a shrink wrapped, on-premise solution with CapEx and maintenance agreements instead
Whilst Feature Parity often sounds like a reasonable proposition, we have learnt the hard way that people greatly underestimate the effort required, and thus misjudge the choice between this and the other alternatives. For example even just defining the 'as is' scope can be a huge effort, especially for legacy systems that have become core to the business.
Most legacy systems have 'bloated' over time, with many features unused by users (50% according to a 2014 Standish Group report) as new features have been added without the old ones being removed. Workarounds for past bugs and limitations have become 'must have' requirements for current business processes, with the way users work defined as much by the limitations of legacy as anything else. Rebuilding these features is not only waste it also represents a missed opportunity to build what is actually needed today. These systems were often defined 10 or 20 years ago within the constraints of previous generations of technology, it very rarely makes sense to replicate them 'as is'.