RAT, #10,
Is the landing roll not effected more by ground speed at touchdown than approach speed in the air? I do not believe that it is because of the multiple effects of the increased air distance.
The key point is the increase in air distance due to the change in approach speed compared with that assumed in original landing performance (at the same wind speed). The change in airspeed / ground speeds are relative, although V squared is important during rollout.
The increased airspeed effects both the flare time and distance, plus any float due to the higher speed than required for the weight. When compared with the expected performance, based on an idealised landing profile based on Vref, then the aircraft would be both faster and further down the runway at touchdown.
Conversely, to retain the same safety margin assumed in the calculated performance, then the aircraft has to shorten the flare time to achieve the same touchdown point, and lose more speed - a fatuous argument where the limit would require a no flare landing with instant speed reduction.
Therefore any unaccounted speed increase reduces the safety margin assumed in the baseline landing distance.
Note Appx 1, para h (2) on page 6, - re adding speed: AC 91-79A Change 1, ‘Mitigating the Risks of a Runway Overrun Upon Landing’
https://skybrary.aero/bookshelf/books/3606.pdf
And note para j (3), page 8, - re minimum acceptable safety margin.