This might be true, but the Dutchman neglected to note that United played a Champions League final as recently as 2011. They also won the league by 11 points in 2012.
To plug the gap created by changing times, Ed Woodward, the United chief executive, gave him a war chest bigger than some countries' defence budget. By any measurement, he has failed to deliver.
Characteristically, Van Gaal would not have any of it. He tends, as befits a man who reportedly hears himself described as a "genius manager" by United's board, to posture as some omniscient being who regards detractors as intellectually inferior.
Rather than acknowledging the shame of tumbling out of the Champions League group phase to Wolfsburg, he berated journalists for not giving sufficient praise to the performance last week of his two young fullbacks.
"I didn't see that you said anything positive for [Guillermo] Varela," he said, almost hurt. "Or [Cameron] Borthwick-Jackson."
So far have United's aspirations fallen, Van Gaal wanted credit for that ignominious evening in Wolfsburg. "We played with Memphis Depay, 21 years old, Jesse Lingard, 22, and Anthony Martial, 20 - and still we could have hurt the No2 side in Germany."
To listen to Van Gaal, you would have thought he had fielded some ramshackle youth side at the Volkswagen Arena. There was no admission that Martial was a talent for whom United had paid 36 million, plus add-ons, or that Depay had hardly been a steal at 25 million, to judge by his meagre haul of five goals since arriving last summer from PSV Eindhoven.
Van Gaal cannot keep up this facade much longer. He is losing plausibility by the day, and already there are suggestions Ryan Giggs - once considered a United "lifer" could yet be tempted by the vacant managerial position at Swansea City.
Intriguingly, Van Gaal did not dispute the possibility. "I cannot speak about the 'if' situations," he said. "First I have to speak to Ryan himself to see if it is true."
He took his players to Bournemouth early this morning (NZT), still cock-a-hoop after their vanquishing of Chelsea, conscious that even his most loyal disciples are becoming restive. A run of three defeats and a draw in four matches is bad enough, but five goal-less draws in the last 10 league games is borderline unconscionable.
The natural logic is that United, deposed from the European aristocracy, must win the Premier League title if the manager is to save his job. But Van Gaal refuses to be held to specific targets. "I have to meet the expectations of five, 10 years ago," he lamented.
