Another point, with their front two players being very close on their map, it doesn't just mean that they were in good positions to link up with each other, it means that they were sharing the load of the touches in the crowded areas allowing each other to move around into space, cause confusion to the defence etc.
We've got Lukaku there and it must be so obvious to the defenders when we're going to play the ball into him. We know that he's not great when the game is like that.
His first touch is much better when he doesn't have time to think about everything to do with hold up play, whether that's simply running, or a turn or a flick type lay off.
That graphic suggests that the majority of times that he's got the ball he'd be under pressure when receiving the ball as there'd be no space, no distractions for their cbs and no team mates close by to help out.
Couple that with us clogging up the centre of the pitch and it's very easy to see why the passing becomes slow and laboured, there are no options to quickly spread the play or play through gaps, the striker becomes isolated so any direct football is wasted as you need higher numbers of players near the target.