I don't know what happened to Leipzig in that game for their defense to be so bad that they conceded 6 goals in the very first league game. This could be a bad sign for Leipzig, who weren't doing well last season, and I see that they'll continue to be good this season. On the other hand, we have Bayern, who were good last season, and it seems that they'll be much better this season. I see them being champions again.
RB Leipzig is a strong team, they were just unlucky to play away in their opening match & have to face Bayern Munich. Bayern Munich, playing in front of their own supporters, certainly wanted to give the best they could & they made it. As for the league title, there's no need to over-debate it. I've often said that Ligue 1 (France) and the Bundesliga (Germany) are farmer's leagues, and they will only belong to PSG and Bayern Munich. If they don't, their season's performance will be poor.
Losing with a score of 6 goals without reply is not because of bad luck but indeed the strength of the Leipzig team this season is very bad or the strength of Bayern Munich is very strong but what is certain is that we can conclude that Leipzig will not be better than last season and they will not even be able to put pressure on Bayern Munich for the Bundesliga title this season.