Well, the league itself is quite entertaining. But I think you can say that about the leagues in Portugal or the Netherlands, too. What matters is competitiveness.
And that's where the Bundesliga has failed in recent years. This is most evident in the Euro League and, to a lesser extent, in the Champions League. After Bayern and Dortmund, there is a gap between them and Leipzig. Everything that comes after that is totally inconsistent.
Dortmund is a feeder club, there is no doubt about that. The business model is to buy highly talented players who are attracted to Dortmund because of its good reputation.
These players then stay for around three years and are sold on at a high profit. The only thing is that you can't make any long-term plans for these top-class players, you always have movement in the team. And in my opinion, it's harder to bring in a philosophy.
Leipzig lives from red bull power, of course. They get the best players from Salzburg because they are higher up in the pecking order. But they are also a feeder club, even more so than Dortmund.
Bayern is simply in a different league because they've worked for it over decades, they've built up the reputation and appeal they live on today and that brings players from other teams into the Bundesliga. There have always been teams that have broken into Bayern's sphere, but they have always lacked something in the overall package to be successful in the long term.
Dortmund is absolutely the closest to that, and I also believe that they have become more robust against short-term problems.
Everything further down the league has good seasons but no consistency because good players are immediately bought away. But that doesn't necessarily only apply to Bayern, but also to Dortmund, Leipzig, Wolfsburg... they are like a hoover.
Another big problem for the league are the traditional clubs that have slipped into the second division, some of them big names from the past that would give the league a much greater appeal, e.g. HSV, Schalke, Werder Bremen, Dynamo Dresden ( yes ) or a cult club like St. Pauli. Who wants to see Fürth, Augsburg, Bielefeld, Hoffenheim or Mainz internationally?
All in all, the league simply lacks the financial power and the worldwide reputation of the premier league or the linguistic connection from la liga to South America. Personally, I believe that the situation in the league will be cemented because the ship has sailed for the clubs further down the ladder in terms of money. (like for example for my hometown club cologne)