The difference here is that Bayer Leverkusen are capable of handling most of the big teams in the bundesliga whereas the same cannot be said about Frankfurt and at such it would be very easy for the Leverkusen side to suddenly overtake Frankfurt soon enough as the season progresses. Frankfurt's inconsistency will be a determining factor and an advantage for Leverkusen who might take advantage of Frankfurt's mistakes this season to go above them because as it is right now in the bundesliga, the only team that can compete favourites against Bayern Munich is the Leverkusen side.
Yes, only one point, so it will not be difficult for Bayer to reduce this gap, there are already 7 points between them and Bayern, which will be much more difficult to reduce and so far I think that Bayern will not allow this to happen, because the level of opponents in the Bundesliga allows them to feel comfortable. But Bayer at the beginning of the season lost a lot of points with teams like Werder, Holstein, Bochum, if you want to defend the champion's title, you need to beat such teams.
I don't know what went wrong for Bayer Leverkusen at the beginning of the Bundesliga season; they lost a lot of points even to the clubs they were meant to beat easily in the league, but they failed to do that, just like you mentioned, which has given Bayern Munich the advantage to lead Bayer Leverkusen with 7 points in the Bundesliga table. I know this is a new Bundesliga season, and it is not possible for Bayer Leverkusen to maintain the same performance they displayed last season in the Bundesliga, but they should have put in a good title defense, which would have made the Bundesliga League more competitive this season. With the performance of Bayern Munich this season, it will be hard for Bayer Leverkusen to close the gap between them and Bayern Munich in the Bundesliga table.