Bayern Munchen still has a chance to retain the trophy, and there is still hope for them to overtake Laverkusen to take over the top of the standings. many matches have not yet been completed, the competition is only halfway through, which means there is no guarantee for Laverkusen to go unbeaten in one season.
Yeah of course Bayern Munich still has a chance on the trophy becaue there performance is also impressive but however before they can get to were Bayern Leverkusen is on the table is actually going to take them time because with the current performance of Bayern Leverkusen there chances of losing any match now is very small and the only way Bayern Munich can take over the first position on the table is if Bayern Leverkusen will lose two matches or lose one and draw one match, then if Bayern Munich wins two matches they automatically become the first position on the table.
So for now considering the clubs that may likely face Bayern Leverkusen, is very obvious that those clubs may likely lose against Bayern Leverkusen because Bayern Leverkusen is a very strong team compare to them, especially there next match against Venezia on the 7 January they will not take Bayern Leverkusen much of a time to win them, so perhaps just like you said there are still a lot of matches yet to be played so let's see how the end of the league will be.
We see good performance from Leverkusen during this season but that's not a good reason to say Bayern Munich is not going to win the Bundesliga title anymore, Bayern Munich is a team with experienced and expensive players like Harry Kane in their team, and that usually has many better chance than all other teams in the Bundesliga. I even think Leverkusen will lose their place soon in the table to Bayern Munich.