While he initially finds great joy in his visit, the nostalgia causes him to struggle to remember that he is now a man, as he grapples with his own mortality.
This could suggest that technology is impure or damaging, except that the same paragraph contains a lengthy reminiscence in which White rhapsodizes about his boyhood affection for an old one-cylinder engine.
White references this in the final lines:I watched him, his hard little body, skinny and bare, saw him wince slightly as he pulled up around his vitals the small, soggy, icy garment.
As he buckled the swollen belt suddenly my groin felt the chill of death.White realizes that although human lives are by themselves transient and insignificant, experiences are immortal.
In spite of the increasing amounts of technology, his son still has the same experiences that he had when he was a boy – sneaking out in the morning, being amused by the dragonflies.