Who said he hasn't done anything behind the scenes? He was brought to the club by Moyes and Moyes is someone that is very good at understanding how a club should be run when it comes to scouting and applying data. And it was Moyes who brought him to the club for the purpose of him revamping and restructuring United's youth academy and scouting/data analytics departments. And he arrived at a time when according to reports we had one full-time scout (Jim Lawlor) and a almost non existent data analytics department. And Murtough has a history dating back almost 20 years, of him being the figurehead at various different clubs doing the work I've mentioned above. He doesn't take part in the recruitment but puts people in places who do identify transfer targets. And him being involved since 2020, doesn't mean he was setting the directive when it comes applying a football blueprint at first team level. That honour belonged to the first team manager and always has done at the club until Solskjaer was at the helm.
Now Murtough’s in a position where we can judge him at first team level. Before his DoF role was consigned mostly to the youth team and there's evidence for that from revamping and restructuring the youth/scouting/data departments to beating out many clubs for the likes of Hannibal, Kambwala etc and dealing with agents like Jorge Mendes. The final call on youth signings was made by Marcel Bout and the final call on signings made at first team level was done by the manager and there's reports backing that up.
He got this job because he's done a good job at revamping/restructuring the club at the youth/scouting and data analytics departments, when those departments were reported to have fallen years behind our rivals. He created the structures and mechanisms from almost scratch and put together a scouting network that was reviewed by a site online (TGG) who regularly have prominent scouts and heads of football from top clubs on their podcasts, who said that it was one of the most impressive lineups they'd reviewed.
He's a football man going back all the way to helping Wayne Rooney come through the ranks at Everton to modernising clubs when it comes to data analysis/scouting etc.
Having a DoF who has created the departments at any club is a advantage. Because like Dan Ashworth said on a podcast last year, 'it's about keeping the wheel moving and making sure the different departments are functioning to a optimal level'. That's basically the job of a DoF/Sporting Director, and being the architect of the processes and roles created is a big advantage. He's also assisted by top people who have vast experience working with him. People who he gave roles to, people like Henny de Regt and Marcel Bout etc who are heads of their respective departments and have vast experience of both working and understanding the game at the highest level.
I didn't say he hasn't done anything at the club but it would be naive to blame him for the failures at first team level of others, when there's plenty of evidence of him being involved on the youth development side as well as being the director at overseeing the revamp/restructuring at the club and also acting upon the scout recommendations by dealing with agents for the purpose of signing youth players like Hannibal, Kambwala, Amad etc.
Below is a 2020 article from TGG, who reported that Murtough was going to head the development of a data science department. This article just sheds some light on who Murtough is and what his back ground is when it comes to the football/data/scouting side.
https://trainingground.guru/articles/murtough-leading-development-of-man-utd-data-science-strategy