I wonder if it is more like "give up" feeling. They were going for the title and they did their best, failed of course but they tried their best. After they realized that they can't get it and Inter did so well, they might have given up on the league.
Yes, they could have at least kept the second place, but they didn't see the point, not like there is a big money difference and team is responsible for it not the players. So, they just maybe gave up? That would be very weird but not unheard of, some teams just crumble after their goal is taken from them. I think Juventus is the type of team that goes for the title, and when they fail to do that then rest doesn't really matter to them anymore, they feel like that is all that matters.
Juventus is not ready to win the Scudetto title, they are still losing to Inter Milan both in terms of strength and level of concentration this season. Yes, I don't think they gave up, but they no longer have a chance to compete with Inter Milan. For this reason, Juventus this season is only targeting a top 4 place to play in the Champions League next season. As you said, Juventus needs to make changes to be able to compete next season because this season they are inferior to Inter Milan.
For second place, of course Juventus has the opportunity to take it back because for now they are only 3 points behind AC Milan and that is quite a close distance. For Allegri, of course, the target of finishing in second place is not their target for this season because finishing in 3rd or 4th place is of course the same, but the failure to compete with Inter Milan is certainly quite disappointing for them.