Exactly, many reasons can be the basis of a team's failure to be able to compete for trophies, even though it is a big club that has a long and glorious history in previous years. If you look from the other side, i actually think a coach who decides to join a big club will have a heavier burden, because the fans will raise very high expectations of the coach to be able to bring their favorite club to become champions, not only that, to be able to adapt to the players is not an easy thing, to get a suitable strategy requires patience and strong leadership.
Usually the coaches who transcend from a smaller team to bigger one usually has a bigger burden of proving a point of how well and capable they are so they can still keep their job and make name for their self. The expectations from fans and the team management does keeps these coaches on toes for them to deliver on their job well, building strategy to keep them very outstanding in their league takes time but some fans do not have that patience to wait for that time and that is why they quickly judge the coach about their performance.
Maybe that's why coaching is one of the most ruthless roles in football. If the team is doing badly, you're the first one to be sent off with the team. It doesn't matter if it's Real Madrid or a team in the lower leagues. If things go wrong, the manager is seen as responsible. That's why the role is actually very ruthless and coaches are now acting with this knowledge. Coaches who transfer from small teams to big teams are aware of the risk they are taking and they are taking a big risk by accepting this challenge.