After watching Inter this season I think the other teams will really need to make a huge progress this summer. 
Because the gap is just enormous now. Maybe you will say Napoli were also like this in the prior season and failed later on. However Spalletti left the team which caused big problems to start for Napoli right after.
There isn't such thing for Inter. They are moving on with Simone Inzaghi. I believe they have the best squad in the league at the same time. In this situation it wouldn't be seeing them winning a back-to-back title unless we see some reaction from another team.
Intermilan this season has a squad that is indeed perfect enough to win the scudetto, every line in their squad is filled with players who are very experienced and also have quite good skills, so that making the performance and stability of their club this season very perfect even though it is not strong enough to compete in the Champions League, Intermilan and Napoli of course have significant differences in terms of their team management, Intermilan is more inclined as a team that does give a lot of trust and freedom to the coach to build his squad, while Napoli, of course we all know how the owner of the club often interferes in the affairs of the coach so that Spalletti left Napoli last season after winning the Scudetto. Because the gap is just enormous now. Maybe you will say Napoli were also like this in the prior season and failed later on. However Spalletti left the team which caused big problems to start for Napoli right after.There isn't such thing for Inter. They are moving on with Simone Inzaghi. I believe they have the best squad in the league at the same time. In this situation it wouldn't be seeing them winning a back-to-back title unless we see some reaction from another team.
Next season will of course be a big challenge for Inzaghi to defend their scudetto, because if we pay attention after Juventus managed to win the scudetto back-to-back, of course no other team can do it in Serie A until now, many Serie A club clubs this season have made coach changes including Napoli, so I think next season Serie A will be very competitive because indeed every coach starts trying to overhaul their squad with Bring in new players who are better.