I disagree with this, of course its a reason. I don't think there is anything wrong with that strategy, if everyone is implementing as they should. However the real issue is we that don't implement it consistently, and there's a very good reason for that this season imho, and its the lack of stability in the back 4, and whoever is playing in front of them. The only run we've had where it was consistent was the first 5 games, and we won them all without conceding a goal, so it does definitely work.
We've lost 4 league games, 2 of them we should have won West Ham H, and Spurs A ( we didn't because we didn't take the chances provided), 2 of them we were well beaten Liverpool H, and Stoke A. We've also lost 2 CL games, one of which we blew by not taking our chances early on, the second by conceding a sloppy goal, and being unable to recover from it.
I don't know the stats, but one of our biggest issues is not taking our chances consistently, we've had games like Newcastle and even Monchengladbach, where we can destroy a team in minutes with clinical finishing, then others like Spurs and West Ham, where we have been well on top and missed a bag full. I'd wager we've had more shots on target than anyone else, and yet taken a smaller proportion of the ones created.
Both issues highlighted are down to individuals for me, the lack of consistency in defence to operate the high line effectively (mainly down to constant changing of players, this time enforced), and the missed (often easy) chances.
The manager has certainly made mistakes, don't think there is any doubt about that, but its not solely on his plate like some would suggest.