Humour me.
Let's say the Dutch plumber stinks the place out worse than Moyes. He's foreign, he's taking over a massive club with huge expectations and a squad that is low on confidence, thin on quality (relative to their closest 4 or 5 competitors), and less cash to splash. Can't see them outspending City and Chelsea in the post-WC frenzy, and RS and Spurs will spend close to MU if the past few years are an indication. And he's got to do quite an overhaul of the squad, lets not forget this is Man U, they don't shop in the Champo or Scots Prem and certainly not at Sligo. So he's got to lay out a lot of money getting world-class players, with Chelsea/City competing all the way, not to mention the big spenders from other leagues. He winds up with an expensive squad with a lot of new faces, up against far more settled outfits and a league that's spent last season smashing the Old Trafford fortress proper. If things go south he's not going to be given till the last couple of games of the season then, is he...so they fire him and replace him with someone else, encore, and before you know it they're Spurs in red.
Is it really so impossible?