Of course he's done on the market. This is the guy who famously said bringing in more than two or three players will destabilize the squad.
I'm also not surprised that we've found it difficult to get rid of players we don't want because, presumably, Wenger still has control over outgoings and is probably hesitant to let players like Gibbs or Lucas Perez leave for less than what he believes they are worth.
Signing a striker was important but once we spent the money on a striker, it never looked likely that we'd make another big move. If Madrid or Barcelona have some scrubs that get booted from the club due to other moves maybe Arsene goes for a sneaky bargain. He loves that.