This is a disastrous start for Ten Hag, make no mistake about it. It's not the players leaving per se, it's the value of the 'assets' that's walked out. This was entirely foreseeable and they've had plenty of opportunity to address it.
Pogba was always going to leave and they've had barely any good performances from him. All the United lads I know are glad he has gone. For the club, that's £90m that's just walked out of the door.
Last year, Lingard had been outstanding for West Ham. He wanted to stay, West Ham wanted him, United didn't want him. The logical thing to do would be to take whatever fee was offered and use the freed up wage and fee on someone else who did want to play for the club. They were spiteful and wanted him back, knowing he would leave a year later on a free and barely played him this season, it's just astoundingly bad management! Not only that, what message does it send to other players?
I don't think Lingard is a top 4 player, but he's plenty good enough. A good manager like Moyes or Howe will make him into a £50m player. He showed up at West Ham and did a great job for them. Why couldn't United get something out of him? Bad management. Simple as that. That's why Pogba looked poor. Give Pep them players and they'll be world class and that's the difference.
Whether you rate these players or not, they are not crap. Pogba will go back to Juventus and start playing like he did and I bet Lingard will go to Newcastle/West Ham and start playing like he can. These players aren't bad players, they were badly managed. United have - in effect - lost £150m worth of player for free. That really does take some doing and give a strong impression that the club is run like a dogs dinner and that the dressing room atmosphere will be toxic. Matic has also left and whilst he's not worth much, it's more experience walking out.
They really are a lesson is how not to run a football club.