I recently took a bus ride. Prior to departing the stop where I boarded, the driver did not deliver a speech informing me that "in the event of an unexpected loss of tyre pressure I will carry out some rather unusual steering corrections"
Nor, I imagine, had the unexpected loss of pressure occurred, would he have said "We have a slighlty unusual situation here, which I thought I would explain to you, and when I have finished, if I have some spare time I will start to think about what to do about it."
Pre flight briefings cannot cover everything and are so rarely listened to anyway (I must be one of the few sad old farts who does listen every time even though I am an SLF of some seniority). Qantas, Ryanair... The crew did what they are trained to do and without fuss.
Maybe aircrew should announce routinely when at Top of Descent "we are now starting to plummet towards Heathrow (or Gatwich or Stansted or whatever)
It would take away the terror of passengers or at least deprive them of the hyperbole when interviewed afterwards