I have been saying for a few years now that Bundesliga top teams need an anti Bayern clause, whatever happens dont sell directly to Bayern. It weakens your position greatly.
What they should do now with Hummels is what they should have done with Lewandowski. Sell to a foreign club, renew or let him play ball boy for a year.
Its a combination of an inferior mindset and lack of ambition why they continue to bend over for Bayern. Same goes for all bundesliga clubs.
What we are heading towards is Ligue 1 type domination in every league but the epl, in 10 years all top 6 leagues will be draft competitions for mighty rich epl where 1 team reigns supreme over the rest due to money difference.
Players going 50+ a season will be common and unimpressive due to it being outside epl.
It will all become very boring and continue till we get a european superleague that might excist next to the epl or with it eventually.
I hope we will be able to keep up post Messi era, I can easily see us fall off with the way the board is managed(especially financially) and end up in a Dortmund like positon (without selling directly to Real).