I agree with you, it will take several seasons for Man United to appear impressive again and repeat its glory like the Ferguson era. However, there are many things that must be addressed by club officials in the future, starting from managing academy players, recruiting coaches who are in line with club culture, and of course recruiting new players who are not haphazard.
We can see now that almost all of United new recruits at exorbitant prices have minimal contribution, and key players who have played for The Red Devils for several seasons also appear far from standard, although not all of them are like that. So it is very reasonable that now most people avoid betting on their winnings because it is not very convincing at all.
It is very likely that The Red Devils will end the season without any trophies, and what will hurt most is failing to finish in the UCL zone at the end of the season. However, in terms of a decline in performance, United was fortunate that they were not alone, Chelsea, who also has status as an elite EPL club, also experienced the same thing, even Pochettino squad had an even more tragic fate.
During the two seasons Manchester United was coached by Erik Ten Hag, there were no significant changes, but in his first season, Erik succeeded in bringing Manchester United to finish in 3rd place in the standings and qualify for the Champions League. But in his second season, Erik Ten Hag was unable to maintain Manchester United performance because until week 20, or to be precise, they had played 20 matches but they were still stuck in 8th place in the standings. I think Erik Ten Hag is not a coach who will be able to bring Manchester United to success like the Ferguson era. He often makes trouble with his players, such as his incident with Ronaldo and Sancho. so that the coach incompatibility with the players will make it quite difficult to see that they can achieve their targets.
Not only that is a big problem but also the recruitment made by Erik Ten Hag is also not able to shine well under his coaching. This season it is possible that Manchester United will finish outside the top 4 which will most likely have a bad impact on Erik coaching career because he could be fired again if that is the reason management writes a letter of dismissal to Erik Ten Hag.