Don't think its about players 'not caring', but its quite possible they don't give every match their best efforts, or as they say "bring their A game".
Last season once it became clear we were out of the CL and unlikely to make the top four, very few of our players, even the stalwarts like De Gea were bringing their B (in some cases C) game!
The performances against Huddersfield and Cardiff were devoid of any real effort, from individuals and the team as a whole; why I am not sure, money, training, playing out of position, lack of team ethos, I don't know, but one things for sure if we start the new season like we finished the last, our main concern will be staying in the Premier League!