This is already addressed in the article, e.g. here:
There might, however, be a dark side to the story. There is
a good reason we were designed to have finite sensitive
periods. Takao Hensch, a Harvard neuroscientist, has
written that plasticity takes a lot of energy: It’s
exhausting to keep all your neural circuits in a dynamic
state. Restricting it may protect the brain.
and in the paragraphs thereafter (I don't want to quote them here in full).
