As Robert Johnson observed in "Thunderbolt"... "They never learn.." as he dove down behind a Bf-109 (lighter) trying to escape his P-47 (heavier)..
It's a combination of gravity, thrust and drag. The plane with an excess of thrust over drag will accelerate -faster- than a plane with less of a thrust-drag delta. The faster accelerator gets there first, as gravity is the same for both.
In the quoted instance, the reason "they" never learned was that Johnson killed them, and whatever "they" had learned died with them, Johnson coming down behind them like an anvil and blowing them out of the sky.
And from the P-51 flight manual...