Fergie created a structure at the club which he relied on to sign players hence he trusted the judgement of the scouts. Fergie wasn't identifying the players to sign but he was rather overseeing the staffing and strategy on the football side of the club and hence he set the direction for the football structure to follow. Wenger did the same at Arsenal when arrived in 1996 and created a recruitment structure which was led by Damien Comolli.
All the top teams sign players by working with their head coach. Rangnick has even gone on record and said he didn't sign a first team player if the head coach didn't agree.
Mourinho and Solskjaer went against the grain and utilised people independently from the club's recruitment structure to sign players. It was reported that the scouts told Woodward about Maguire not being any better than the options that the club already had it's disposal and he shouldn't be signed under Mourinho. Mourinho then went to war with the club's recruitment structure and started maligning them in public by stating how good West Ham's scouts were due to them identifying talents like Issa Diop. Solskjaer comes in with Phelan as his advisor and Woodward seemingly ignores the head scouts and allows Maguire to be signed with Maguire's former manager at Hull, Mike Phelan likely playing a key role.
Both Solskjaer and Mourinho were reportedly relying on their personal scouts and David Ornstein reported about Solskjaer not having communication with the club's recruitment department and Sokskjaer and Phelan were seen scouting players in several stadiums around Europe. Fergie and Wenger didn't operate like this and they developed their club's football structure and utilised the resources of their club's which benefited both the club and manager.
Erik ten Hag from the evidence at hand is working with John Murtough and the scouts, data and video analytics teams. He doesn't have independent scouts from what I've heard and read, and he's part of a football structure that is looking to streamline the process, which has only started happening now since Fergie retired. So if ten Hag is interested in signing someone he's familiar with, he has to inform the heads of scouting who will run the rule over said players. And it has been reported about ten Hag asking the scouts to compile reports on players he knows about. And that is normal at clubs who have a streamlined approach to their football structure.
Paranoia is deep among many fans on here, which is understandable. But the only issue I see right now are the owners who need to back the team below. And this is a team of people who need the backing on the football side of the club.
John Murtough: Head of football
Erik ten Hag: Head coach
Andy O'Boyle (deputy head of football)
Matt Hargreaves: (transfer/contract negotiations)
Jose Mayorga/Simon Wells (head scouts)
Dominic Jordan (head of data science)
And the article below from the people at the transfer ground guru from January 2017, goes into more detail about the scouts that were brought in and how no stone was left unturned in bringing the best in class recruiters.
https://trainingground.guru/articles/man-utd-scouts-summoned-for-meeting-after-huge-overhaul
Woodward put Lawlor and Bout in charge of the scouts at first team level and allowed Solskjaer and Mourinho to operate independently from the scouts. And that there is Man Utd's problem and why we couldn't develop the football structure to a high level. Liverpool had the same issues under Rodgers until they hired a head coach in Klopp who came in and revived a much ridiculed football structure led by Michael Edwards.