Well, she's had a long and distinguished service in the pax role.
What isn't yet clear is the true reasoning.
Is this decision a precursor to scrapping the C1Ks to save money?
If it's airworthiness or equipment as has been grasped by some on here, then why is it OK to fly a Tanker (with 20-odd seats too) in GA airspace without that kit, but not the pax jets - are our crews that expendable?
My guess is the former is true - when the appropriate sums are added up, charters are cheaper than the C1K fleet.