Yes, that's the part here - you die without factor VIII. Its why severe hemophiliacs almost always died before factor VIII because available, and why almost 100% of them had HIV and hepC in the window between those viruses entering the blood supply and 100% testing / heat treatment (which is darkly funny because one of the trials involved was about heat treatment, seems to work for HIV but not for hepC).

From what I can tell, the issue is twofold: Informed consent, of which there was very little, but that's not exactly rare until recently, and running the trials on "marginal cases" - hemophilia comes in differing severity, and given the risks of using known contaminated factor VIII using it unless necessary probably wasn't the best idea.