Italy playing in the playoffs to qualify for the WC 2022 is certainly disappointing months after the Euros win, but it is barely new for international teams to break off after major tournament triumphs.

Spain of the late 2000s were an exception and so were the Brazil teams of two different eras. But France failed to do anything special in the Euros after having won the WC in 2018. Germany won the WC in 2014 and then fell off in the next 2 major tournaments. Portugal themselves are failing to qualify for the WC and didn't pull up any trees in the tournaments after the 2016 Euros win.

So while it is disappointing for Roberto Mancini's men, it is an old habit.