When AIDS was new, I think many JWs were "smug" (if that's the right word) about how their "spirit directed" policy against blood transfusions had "protected" them from contracting this deadly disease by abstaining from blood.
Today, I think most JWs are more aware of the deaths from refusal of blood transfusions than any "benefits". The evidence of this, IMO, is that nearly ALL of the JWs I assisted with their "blood card/documents" agreed to accept any of the "blood fractions" that WTS permitted per their "conscience".
When WTS/GB saw the New Light on JWs accepting "blood fractions" (or EPO or any product previously prohibited) then SHAZAM! they ALL HAD A SUDDEN REVERSAL OF THEIR PERSONAL CONSCIENCE.
Likewise, if WTS/GB saw New Light and determined that transfusions would be a "personal conscientious decision" that would NOT bring them negative consequences, the VAST MAJORITY would "change their contentious position" on accepting them in an emergency.