'Some Wenger lunacy' Wenger has been the manager since 1997, he's controlled almost every aspect of the team since then.
He decides who is bought sold loaned, he decides who is paid what and how long their contract is, he decides who the coaches are and what system and style we play, he decides who is selected and who is substituted, the buck stops with him.
So yes- he is somewhat accountable for our failure over the past 7 years.