To answer your question I believe everyone would get the 2 doses and receive SOC should it be needed. However because SOC is better now it's possible placebo and drug arm patients are living 29+ days but SOC may not be making it to 42 days as well as people that were treated with leronlimab and may still just be in the hospital for rehab. If these people got so bad they started having organ failure or put on ventilators, they may need extra days in the hospital but are living past 42 days because leronlimab got their immune system on the right track where as placebo are the SOC just prolonged the hospital stay without benefitting the patient who may have eventually passed after a longer fight with covid. So you can see why looking at a longer span could help even if they only receive the requisite 2 doses.
In the end people will just look at who was still alive on exactly day 28 and who was not which doesn't give the overall picture of if someone is benefitting and getting better and eventually leaving the hospital or lived past 28 because a ventilator kept them alive just a few more days.