Looking for a word that means "a lack of listening skills"
Words like inattentive, distracted, distrait, oblivious come to mind.
Since lack of listening skills as a phrase is broad—there are many ways in which someone can be a poor listener—you might want to just use the phrase itself.
I witnessed a slow transition from awareness and excitement to Wallace's "natural state" - irritable†, discontent, and inattentive‡.
†Note: you may want to change irritability to irritable. Irritability is a noun that is a state of being, while irritable is an adjective that describes a noun's referent; in this case: Wallace's "natural state."
Inattentive (adj.)
- Of or pertaining to lack of attention; not paying attention; careless.
He was inattentive in class and did not do well in his exams.
‡Alternatives:
Ignorant (adj.)
- Unknowledgeable or uneducated; characterized by ignorance.
- (slang) ill-mannered, crude.
Unmindful (adj.)
- lacking awareness; oblivious
- failing to remember or recognize something; heedless
Close-minded (adj.) [alternately spelled: closed-minded]
- unreceptive to new ideas or information; not open to any agreement.