Two things:
I have kept my ears open since becoming an A owner in yr 2000, for the number of A's still existing. The number I've heard the most is around 300,000.
Second - to account for 2% of surviving 15,000,000 T's vs. 5% of surviving 5,000,000 A's, many T's were at end of life during the scrap drives of WW2, while the A's, besides being more reliable, could be considered "prime of life" in rural America.