These lower level interventions don't make all that much of a difference. As the disease progresses your lung capacity reduces. If we put some made up numbers

These lower level interventions don't make all that much of a difference. As the disease progresses your lung capacity reduces. If we put some made up numbers to it, it would look like: 0-50%: Can breathe on their own with increasing difficulty 50-55%: Can survive with O2, BiPap, CPAP, etc. 55-80%: Can survive with intubation 80%+: Dead Each individual patient will progress to a certain point and then either recover or die. The number that will progress to the O2, BiPap, CPAP, etc. level and then recover is relatively small since it's a pretty narrow band where it is effective. AFAIK, most places are skipping the O2, BiPap, CPAP stuff because they use pressurized air. That generates a lot of droplets/aerosols and poses a significant transmission risk. Since there's a relatively small chance that the patient will recover on those interventions they skip them and go straight to intubation.