You have to look at the whys and wherefores of top teams to see why this isn't a particularly big issue. The better the team, the more unfeasible it is to contain the unit over a full game.
Rashford, Martial, Sancho
-----------------Bruno
-----Pogba
If you're not going 1on1 with those players and are doubling or tripling up on an isolated threat, you're leaving gaping holes for others to exploit, which is how top teams breach the dam before it eventually bursts its banks and overwhelms.
Sancho is a great passer and user of the ball. Even if he wasn't a dribbling, close control etc. talent, he could easily get by as a passer and mover. So drawing men in (them closing down and occupying space) simply opens up the field, via passing, for others to exploit, and if a FB and a CB have gone over to Sancho, there immediately materliases space for Bruno to run into, or Martial to go across to, which in turn sets off the chain reaction for their markers and our other players joining attacks whilst having their own men blindsided as they've turned towards the ball all the way over on the right side of the pitch.
Ask yourself which defence wants to be blindsided with Rashford on their outside and Pogba lurking 20 yards off the play. It's then a question of whether a side allows themselves to be drawn towards a single player and/or the ball, or keep their lines/banks compact and organised. Either way, space presents itself.
Sancho, or any player of that calibre, keeps opponents honest and really balances out an attack like ours. Trying to isolate any one of the aforementioned players come with a large element of risk, just as we've seen with other top attacks over the last few years.