Or they can spend the next 20 years cycling through new managers that fail at every step on the way, that is the way the club used to be run. I have a friend who is an Arsenal fan who celebrated like mad when Arsene Wenger left thinking now they would finally get a manager that could win them the PL, 6 years later and they are no where closer to win the PL today than they were 6-8-10 or 15 years ago. Or Inter Milan in the 90s, spending more money on player signings than the rest of Calcio combined and still failing to win the Serie A. Often the obvious and easy solution aren't getting you any closer to improvement and instead send you on a roller coaster of hopes and crushed dreams. All I'm saying is be careful what you wish for.
Arsenal are not closer? Really?
Wenger stopped winning leagues in 2004, and after CL final 2006 he checked out of serious competition and coached basically an academy preparing talents for top clubs (Barca Madrid EPL etc) to snatch up when they were ready.
Yeah, I know there were other financial reasons they were not competing, but the last 10 or more years of Wenger were really demeaning and the team was being held back because of an emotional cling on the past and on Wenger's stature within their club
What happened when he left? It took only 2(!) appointments to find the guy that will take them to the next level. They trusted the process, and now they reap the benefits. And it's not that Emery was a random far-off appointment, it was also a great appointment
Now, you may have in mind UTD after Fergie, which is the opposite example: a mess with no plan, run by a bunch of crooks in suits, changing coach after coach, and belittling the history of their club.
Well, Atletico are in the Arsenal 2006-2018 era: they cling stubbornly to the past due to emotional reasons, and don't have the balls/courage/decisiveness to make a clean break, say goodbye to him, thank him for what he did in the past, and move forward.
After that they have two roads ahead: the UTD one, which only idiots will take, and the proper one which is the Arsenal one after Wenger
Of course, they can always become the new Arsenal 2006-2018, and also a laughing stock gradually, because they cannot solve their attachment issues.
It's their choice to make