Having read the dialogue between and existing Elder in Alabama and the WT Society posted on Randy's site (Thanks Randy for this scoop), one can see that the Society WILL NOT and cannot change their blood policy anytime soon. Barring some outright coup, the Society will maintain the existing stand.
They have invested so much effort into this. They have received recognition from secular quarters re their pursuit for blood-less surgeries and other blood alternatives and would appear silly if they suddenly backtracked now. I believe that this factor alone is providing the main momentum that is keeping the Society from making any new changes or even explaining their existing stand.
The WTS is between a rock and a hard place on the blood issue. As far as your argument is concerned, you could have tried to make the same point in May of 2000 only to see the WTS make sweeping changes a month later by permitting all blood products fractionated from red cells, white cells and platelets (plasma fractions were already permitted).
I think it is very difficult to try and forsee where the WTS is headed with their policy which is precisely why there is such a need for us to be proactive. The WTS was thoroughly exposed before the medical ethics community and soundly defeated in my view. The unreasonableness of their position is becoming widely known via published articles in various medical journals. The effect of this will not be truly known for years but my belief is that the pressure will continue to mount.
In the meantime, all we can do is try to educate others so that they can make informed, autonomous choices and continue exposing the WTS' irrational policy to all that will listen.