Not sure this analysis adds much to what any follower of the Premier League has noticed: that the gap between the top and bottom has been widening for years. The biggest clubs have money, history, and stability on their side, which helps keep them at the top. But it’s also true that a new middle class has emerged in recent years. Teams like Brighton and Brentford show that smart planning, data use, and strong recruitment can help a club not only survive but become regulars in the league despite the financial imbalance.
In the Premier League, there's a relationship between years in the league and goals scored, but not in the lower leagues. It's bad news for newly promoted clubs.