Gli Azzurri have struggled on the international stage; despite winning Euro 2020, they failed to qualify for the last two World Cups.
They endured four consecutive defeats before head coach Luciano Spalletti was dismissed.
"Norway-Italy? As an Italian working abroad, it hurts even more. I think differently from what you hear or partly hear,” De Zerbi said on Alessandro Cattelan's podcast.
“I feel that it is a period in history in which we are struggling to produce players of a certain level. Surely something must be wrong. I am no one to say whose fault it is, certainly not all the coaches who are taking turns on the bench.
"In the long run I think that it is no longer the time of Totti, Del Piero, Inzaghi, Montella or Vieri in which you did not know who to bring. Now France has these things, Spain but Italy does not. Italy has some strong players like Barella, Bastoni, Tonali, Locatelli; but it is a period in which we are not able to produce a certain level. Against Norway there was no mentality or self-esteem and that is also part of the level.
"What happened: Italy goes to Norway, where it's colder and finds a very strong team. The championship ended yesterday and the season was tough: it's not easy for everyone to prepare for a match like that. I always start with the player and it's hard to find talent now. I really think the level is low. It's everyone's fault who's part of the system."