Unfortunately, Italian teams have not raised the Champions League since 2010, but it must also be said that in the following years there was a chance to win several times with Juventus and Inter last year. Unfortunately they didn't manage to raise it, but I believe that in the years to come and with all these new owners of the top Italian clubs, Inter Juventus and Milan will have further chances to win the Champions League. At least I hope so
Italian teams are not weak. However, they are not interested in spending a lot of money on squad formation. So even though the performance of Italian teams is stable, none of the Italian teams have a squad strong enough to win the Champions League title.
Inter Milan and Juventus are strong teams. And their management is rich enough. If these two clubs target the Champions League title and form squads, then these two teams will be able to dominate the Champions League. But they will not be interested in spending huge amounts to buy players. They will form a stable squad. But I don't think they will try to build a very strong squad.
Unfortunately, in Serie A the management of television rights and performance bonuses are much lower than in the Premier League and La Liga, so the spending on players will also be lower, but spending crazy amounts of money does not give you the security of winning everything and also getting big revenues. Moratti's Inter spent crazy amounts of money and won very little, furthermore he left the company full of debts that still weigh on the company's balance sheet. Unfortunately it will be difficult for Italian teams to win in European competitions, but that does not mean that they will not be able to fight until the end. I still remember when Serie A was the most beautiful league in the world and Italian teams often won European competitions such as the Champions Cup and the UEFA Cup, but these are distant memories now. I hope that one day Serie A will return to being the best league in the world.