The only way for anyone else to ever have a chance, would be getting a rich owner who can spend as much as Bayern, but not that many people could spend 300+ million a year on a team, so I am pretty sure that Bayern is comfortable at the moment and won't face that much difficulty from any other team. It does make the league a bit boring, but it is the reality we have to learn to accept.
Bayern München is not a team that invests hundreds of millions of euros in new players every season. They also invest a lot in cheaper players and then build them up. That's why opposing teams can compete with Bayern even with smaller budgets, they just have to play strategically like Leverkusen did when they won the Bundesliga. Leverkusen didn't invest as much and still managed to do it also!