Maybe that’s true now, it wasn’t a few years ago. I remember watching a match against PSG in the Champion’s League and the stadium was barely half full.

I’ve been to most stadiums in Germany, few were as empty as the BayArena. And of course Bayern has tons of success/Event Fans. The same was true for Dortmund in 2011-13. Success sadly attracts people who might otherwise not be interested as much and there’s not much you can do about it. Maybe the current success will actually fill your stadium for a while.

I know this is a joke but Leverkusen is known to have no proper fanbase anyway