Its media bullshit.
If I do a retrospective, the problem might be located in the early 2000s, though I'll put it a little later in the mid 2000s, right before and during calciopoli. In the 1990s serie A was dominant not just with trophies, but because its teams could easily keep hold of their stars and buy the other leagues' top-stars. Then in 2001 and 2002 two shocking transfers happened when serie A lost both Zidane and the old Ronaldo. Big losses, sure, but the best teams were still very able to stay just as strong by buying the best players from Lazio, Fiorentina, Parma (say Rui Costa, Buffon, Nedved, Nesta, Crespo, Thuram etc.)
Then when Milan were pretty much forced to sell Shevchenko in 2006, and replaced him with Ricardo Oliveira, it became clear that the league can't keep track with the nouveau riche. Calciopoli only speed-up the process. Then year after year, the league wasn't only losing its main stars (Kaka, Ibrahimovic, Thiago Silva, Pogba, Vidal) but the biggest teams were unable anymore to comfortably buy every top player from the smaller teams (Cavani, Alisson, Salah, Jorginho).
Then Cristiano Ronaldo arrived. We managed to out-muscle top team(s) for de Ligt and Inter bought Lukaku for 80 million. It looked like serie A is really coming back. Not there yet, but going forward, with potential to reach the best leagues in some 4-5 summers. This summer Italy won the Euros.
And then this shock. Inter and Milan managed to lose Donnarumma, Lukaku, Hakimi and God knows who else is leaving, while the best teams are pennyless and can't even afford De Paul, Romero, Locatelli and similar players. Right when we thought that serie A could be back, it fell even further behind, without prospect to fight back. Looks like the Super League was the only solution to at least save the biggest teams. Now that's ruined too
