They are humans. You can’t asked them to play like it’s a game 7 playoffs game every night.
They’ve learned how to win and they how how hard it is to make long runs in the playoffs.
Last playoffs, they were way more less physical than the year before. Why? Because they’ve learned that playing physical like they did in 2023 wasn’t sustainable to win a cup.
What you call lack of motivation, I call it energy management. If they can make the playoffs while playing at 80% of their capacity, they sure will. Not all teams have this luxury, but they do.