"Watson can’t adjust its answers to what the other players say and so it simply answers with whatever comes up as its top answer."

This is false, in fact they specifically mentioned Watson learning from the answers of the other players.

In the game, Watson answers "The 1920s" after Jennings answers incorrectly with "the 20s". Basically, it didn't write off its own answer because it thought Jennings' was different enough that it might have been incorrect for the way it was phrased. The same way you might correctly answer "inner ear" after someone else incorrectly answers "ear".