All decent Bundesliga players wanting to either play for Bayern or move to a top team from other league's hurts the league the most.
Cases like Leverkusen from two years ago, Dortmund from the early 2010s, Wolfsburg in 2008 or 09 are the exception to the rule.
Dortmund was ramping up to pose as a rival to Bayern but they fell short. Unless a club emerges with conditions where top players will want to stay and comit to a career there, Bayern will continue to cruise through the league