The Bundesliga is not a low level league, same with La Liga but we do see one or two teams dominate the league, such leagues are considered farmers league. Aside Bayern Munich, which other club can we actually talk about, that are among title contenders for each season against Bayern. There is a notable difference between Premier League, Italian league and Bundesliga or France League, Bundesliga and France League are both farmers league, no need for sugar coating.
Once the titleship don't rotate frequently, we see the league as farmers league, Bayern Munich are capable of holding the league title for a decade without any club defending the title, it takes massive luck for other clubs to win the league, for example how Leverkusen in their best form to win the league.
In as much as I will not want to dispute the obvious fact you have stated, we also need know that we cannot blame it on these top teams either, in the Bundesliga we see that Bayern Munich is the most funded and also the team with the most depth, this applies to PSG in the French league too. You will not have them getting all that capacity only to lower themselves for another team to win the title so they will not be regarded as a farmer league, it is business and a lot is been invested, so they have to do the needful to get returns, if others so desire to not be part of the farmers league, then they should be funded and play right tor meet up with this dominant team.