I agree with TastyChillySauce00 that makes a lot of sense and for me Nottingham has been failing for a decade. If this time he Nottingham failed to get a UCL ticket, it's not something new anymore. And even I believe that Nottingham's achievement this season is just a matter of luck, not about consistent performance.
We can prove what I said this we will see in the coming season Nottingham will not get the same results again as this season.
Apart from luck, maybe we can judge their performance and hard work, I'm sure it's a more complete grouping. But if we look at next season how Nottingham Forest will perform, I'm not so optimistic because there will be competition from other teams. To perform consistently, a good squad is needed and if Nottingham Forest is unable to recruit quality players, then next season they will be an ordinary club.
Newcastle is an example and we can see them last season and the financial capabilities they have made Newcastle manage to maintain at least the top five positions until the end of the season and that is influenced by the good squad owned by Newcastle itself.