The glaring truth for Louis van Gaal is that Manchester United should have coasted through a Champions League group featuring PSV Eindhoven, CSKA Moscow and Wolfsburg. This is no anglocentric view fuelled by Premier League entitlement, but the simple corollary of what the manager’s £250m splurge on 12 players in his three transfer windows should bring.

Van Gaal was given the bulging war chest to ensure crucial Champions League games such as Tuesday’s showdown at Wolfsburg could be negotiated. Instead, the German club won 3-2, and United were dumped into the Europa League. The quarter of a billion-pound spend should also have guaranteed that PSV were beaten at Old Trafford in the previous Group B game. Instead, a 0-0 draw was all Van Gaal’s team could manage and United arrived at the Volkswagen Arena in a perilous position.

The prime factor here is Van Gaal’s scattergun management style. It is a mix of the methodical and the eccentric. His United may be a plodding proposition but a fault line runs through the 64-year-old’s transfer dealings, man-management and team selection.

Van Gaal rejects XI: players sold, released, loaned or frozen out by United’s manager.

For Tuesday’s high-stakes game Van Gaal handed Guillermo Varela, a 22-year-old Uruguayan, his senior debut. It was an odd decision. So, too, was the naming of Nick Powell as a replacement. The 21-year-old was last seen in United colours when Van Gaal’s side were given a 4-0 beating at MK Dons last August. Yet after 69 minutes they were 2-1 down at Wolfsburg and the Dutchman decided Juan Mata’s Champions League-winning experience (with Chelsea) should be sacrificed and that Powell, who has not played a second of senior football this season, could be United’s saviour.

When the left-back Matteo Darmian was injured before the break the Dutchman turned to Cameron Borthwick-Jackson, an 18-year-old with 14 minutes for United on the CV. It meant Ashley Young was again ignored. The 30-year-old has been one of the successes of Van Gaal’s reign, slotting impressively into either full-back position when required. So Young could have started instead of Varela, or he would have been a more comforting sight to his team-mates than that of Borthwick-Jackson trotting on.

David Moyes’s final Manchester United starting XI, 20 April 2014.

But could have, should have is becoming a concerning trope of the man whose much-trumpeted philosophy is as puzzling as the Van Gaal buy-and-sell policy.

Ángel Di María was the quick, world-class wide player Van Gaal yearned for when taking over in July 2014. He was acquired for a British record £59.7m and lasted a season before the manager discarded him. A footballer whose dribbling and game-breaking talent made him man of the match in Real Madrid’s Champions League triumph two months before joining United seemed almost instantly to make Van Gaal suspicious of these same abilities. So, why buy him at all?

Di María heads a long list of Van Gaal rejects who might be swapped for those he has brought in (and retained), which poses the question of whether the manager has significantly improved the squad with the £250m investment.

Others through the exit door include Shinji Kagawa, Danny Welbeck, Rafael da Silva, Darren Fletcher, Javier Hernández, Jonny Evans, Nani, Tom Cleverley and Robin van Persie plus the loaned Adnan Januzaj, James Wilson, and Tyler Blackett.

Manchester United starting XI v Wolfsburg, 8 December 2015.

In have come Memphis Depay, Bastian Schweinsteiger, Daley Blind, Morgan Schneiderlin, Luke Shaw, Marcos Rojo, Darmian, Anthony Martial, Ander Herrera, plus the loaned Radamel Falcao, who was patently not fit or good enough and is now at Chelsea.

Some of these decisions were correct. Van Persie, Fletcher and Cleverley are among those who needed to go. This is the least required of Van Gaal, though. Assessing player talent is a big part of the manager’s job specification, after all.

But there is also a concerning mishmash of the awkwardly managed (what does the fast-thinking Herrera have to do to convince?), the erroneously bought (did Van Gaal really require another plodding 30-plus midfielder in Schweinsteiger to complement Michael Carrick) and the no better than what he had (Depay and Rojo for Nani, Kagawa and Evans fall into this category).

There seem to be only two players who have truly impressed Van Gaal – Shaw and Martial. Two from 12 brought in is a poor ratio for any manager. There can be some mitigation in the failed attempts to buy Thomas Müller from Bayern Munich, Neymar from Barcelona and Cristiano Ronaldo and Gareth Bale from Real Madrid. There is no issue with this ambition. And all of these transfer targets remain works in progress for Van Gaal and Ed Woodward, the executive vice-chairman.

Yet have United evolved under Van Gaal? He suffered injuries on Tuesday night, as Wayne Rooney, Phil Jones, Rojo, Herrera, Antonio Valencia, Shaw and Schneiderlin were unavailable. But Manuel Pellegrini has had to deal with a similar high number of maladies and he guided Manchester City to a fine Group D-topping victory on the same evening, with a 4-2 defeat of Borussia Mönchengladbach.

City now have a better chance of a favourable last-16 draw and of progressing deep into the completion. Their ambition to enter the rarefied air occupied by Bayern, Real and Barça remains on track.

For United the gloomy truth is that under Van Gaal they appear a million miles from adding to their three European Cups.

They are the club with a £250m investment by a manager who has taken them into the Europa League. It is just not good enough.