Didier Deschamps warned Olivier many times about his lack of play time, he asked him to find a team where he would get more minutes, he never listened. Giroud was also goalless during the World Cup.
Benzema is definitely a world class player, he's our only good offensive player since Ronaldo was sold to la Juve. The second-best goal scorer after Karim this season is Casemiro, with 5 goals... Even with the lack of offensive support, we almost won La Liga for the second time in a row and we went as far as possible in the CL, but we lost to the future champion.
His first preparation game against Wales was pretty good, he had many chances, but was unlucky. Against Germany he had some chances, unfortunately they were offside, he made an awesome pass to Kylian, who found himself alone, but was tackled from behind by Hummels, Karim participated in the first goal. I missed the game against Hungary, I can't say much about it.
That been said, he needs to score goals, it's his job. It's all good to get some opportunities, but as a striker your job is to score and for the moment he's not doing that. I'm disappointed in him, but it's not too late to do something.