Cole reckons not even landing top target Sancho would make his old club a title-winning team.
The former striker, 48, said: “I want to sit here and say Man United will win the league this season — but then I look in the mirror and say, 'Why am I lying?'
“There's no point me trying to dress it up. We have to be honest and United are two to three years away.
“It might take them a bit closer, but we are saying now that one player could possibly take you a little bit closer to winning the league when you see Liverpool have added two very good players, Manchester City have added two very good players.
“Look at Liverpool, it has taken them 30 years to win the league and they have gone through loads of different players to get there.
“And you look at City, how many years did it take them to win the league, how many players have they gone through?
“I am a realist. I know if they brought in Sancho he would improve Manchester United. Would he improve Manchester United to the point where they would blow away the other two teams? I am not quite sure about that."