The Bundesliga League has not been very competitive because other teams apart from Bayern Munich and Dortmund don't spend money to sign quality players into their club, last season Dortmund performance was terrible, they were able to compete with Bayern Munich because Bayern Munich was not in good form . Bayern Munich is just only the team that are doing things accordingly to still have a quality performance and to win trophies. I consider every other team as not yet ready to win trophies, because if team like Dortmund is interested to win trophy I think they will work towards it and do things the right way.
If we consider how "rich" leipzig is, they should be up there fighting for a top spot as well but they keep failing. They end up raising good players and selling them and making profit, but they already should have a good profit and money in the bank.
So if they really really wanted to, and not just have a sustainable football culture, they could spend a ton, like hundreds of millions of dollars, in that case they would get all the great players and build a team that could get the title. For some reason they prefer this system better, not winning anything, but always around the top, like top 10 guaranteed for them, top 5 not a shocker, and not losing much money neither, that's how they keep doing it for the time.