Liverpool's attack hasn't looked good either, but still watching them vs United and it's obvious they are a much better attacking side. VVD is immense at the back and their defense is certainly better, but for me the main difference in defense is teams like Liverpool (and more so City and Chelsea) are such attacking threats that teams not only play deeper but are cautious in bombing their fullbacks forward.
For instance, I happened to watch United, City, and Liverpool's matches against Brighton. City and Liverpool's defenders didn't really have much to do as Brighton played deep and their fullbacks didn't get forward. Both teams could have easily more. In contrast, against United Bong and Montoya were constantly getting forward and their backline wasn't that concerned about defending deep. Granted Brighton were at home, but I would be shocked if they played like that in the reverse fixtures vs any other top 3 side.
I'm actually not shocked that players like Linelof look so terrible. Why have a ball playing defender playing so deep? Many of the best ball playing defenders in the world would look out of place in system where they consistently defend deep.
Main takeaways:
1) Most modern Premier league teams are good on the ball. When given time and space, they can create very good chances.
2) Managers like Pep, Klopp, Sarri, and Poch have systems that do not allow the opposition any time on the ball. The trade-off is the increased exposure to counterattacks and the amount of ground players must cover, but it seems the pros outweight the cons.
3) United has the quality to play on the front foot and force teams to setup to defend deep. Between players like Pogba, Sanchez, Martial, and Rashford there aren't many teams who can go toe to toe with United. Sure, they will concede goals and perhaps won't be as good as an attacking unit as City or Liverpool, but they should blow away almost every other team.