He wasnt brought in to reset the squad and have them play a modern brand of football before consulting on a restructure and overhaul?
You should follow the club a bit better if you think otherwise. He wasn't brought in as some new manager bounce sole remit. You should not compare him to some Benitez or Alardyce sort of expected impact. His work takes time and buying into. Everyone knew that, and we hired him for wider reasons than these 4 months.
It was reported in various media that United wanted to hire Rangnick as interim when they were considering firing Ole. The job was interim manager.
Rangnick was the one who wanted more than interim. This is unsurprising: he's not a professional manager anymore, he runs a consulting company instead, and he had a contract to consult for Lokomotiv which he'd need to drop in order to join United. After looking at various candidates (normal manager types like Ernesto Valverde), United eventually relented and offered him the two-year consultancy. Again, this was reported
before and after Ole was fired, from both sides (sources at United, sources close to Rangnick).
When Rangnick was hired, the statement put out by United said that his goal was to have a
"successful season." He later explained in an interview that this meant hopefully qualifying for the CL and advancing in the competitions that United were in, like the FA Cup and CL. This is the typical responsibility of an interim manager.
He also said that "
the reason the club contacted me in November was the fact we conceded too many goals too easily. We reduced the number of goals conceded but the way we defend is still not standard we need in order to be a top-four club." Becoming more defensively solid is basic, bog-standard 'interim manager' responsibility, it has nothing to do with playing a modern brand of football.
In February, Rangnick was saying "right now, I think we are focused on winning those games and it doesn’t make sense to speak about any things that have to be done in the summer. 'With regards to getting the right players or doing some changes inside the squad,
my full focus is on developing the team's performances and hopefully winning as many games as we can."
Sky Sports reported in March that United had not even defined Rangnick's future role yet, because they "took the decision to put strategic planning on hold to
allow Rangnick full focus on trying to salvage the season through coaching." The same article says that "
the notion Rangnick could operate as a loose version of a sporting director, helping John Murtough and Darren Fletcher knit a solid strategy behind the scenes,
has been labelled 'hugely unlikely.' Sources have intimated his role in all probability will be centered around sharing insights on innovation, scouting and linking the club with bright football minds
rather than fundamentally altering their set-up."
All of that contradicts the idea that he was brought in to "change into a modern brand of football and restructure and overhaul the setup."
It's all very obvious. You don't hire someone to manage for six months if their job if "their work takes time and buying into." Ten Hag does not have the same ideas and neither does Pochettino, the original first choice. There is not that much continuity there other than some vague notion of "being modern."