Because the Scudetto was decided months ago. We're chasing mathematically clinching it, but for all intents and purposes it's been over for a long time. The 2nd placed team in the league fielded a B side today because they're prioritizing their Europa League game next week (rightfully so).
Our opponents since losing to Atleti:
Napoli
Empoli
@ Udinese
Cagliari
Napoli only stands out because of reputation, they've been nothing special this year. The other three teams are fighting relegation, which to some degree works against us because these games all meant a lot more to them than they meant to us. We're playing one game a week, so it feels like an eternity to get to these games, two of these games were on Monday's no less, we're not getting any benefit of an early game in the match week...I bet if we were still fighting on the Champions League that our performances would look better. We'd need it in order to stay sharp for those CL games. What do we have to stay sharp for right now?
I expect a strong display against Milan. That's about it. Otherwise, what we've seen the last few weeks...get used to it. It's not getting any better the rest of the season. We're playing out the string and waiting until we can celebrate the Scudetto ceremony in the last home game of the season.