No idea about the situation in Germany though.
You support the german team, you´re happy if they score, win or advance - but you´re alright as the
"neutral observer" if they lose and drop out
Of course i see the advantage for the Bundesliga if Bayern and Dortmund win the international competitions (money, respect, international spots). So this is definitely a PLUS. And depending who they play, i would even say, i would root for them (Bayern vs. City is 50/50, as i would think it´s funny to see the hateable Bayern and the hateable Bayern lose to City, who basically fire their manager to pick up a bigger one and then beat
him; but against Real and Atletico, which are full of dirty tricks or showmanship/Real, i would root for Bayern of course; as well as Dortmund to win the EL).
But as it is more a supporting from the brain, which says "you´re german, root for Dortmund vs. Shaktar" for example, and not a rooting from deep-down in the heart for your home-club or National Team, the brain will also switch it off pretty quickly, if, in this case, Dortmund would play poor and drop out to Shaktar.
But this is a feeling that has changed a lot over the years, at least for me. And i believe, even more for little kids. In my younger days (34 now), it was just possible to love or hate Bayern. Today, you could respect them and hope for them to advance, they are more likable. I had my Manchester United shirt (don´t tell anybody) with Cantona on the back and i really wanted them to win against Bayern in CL´99, even more, as Bayern beat my team Kaiserslautern in the quarterfinals 99. That final was funny as hell. Today, even if i like the german players at Arsenal or Leicester or whatever, I would root for the german teams in general. In 99, they had quite a few players who were very unlikable like Kahn, Basler, Matthäus, Effenberg and so on. Those guys were douchebags, although Kahn changed a bit since then.
Today, you walk around here (400km away from Munich and Dortmund) and you see kids with shirts from either Dortmund or Bayern or Team Germany. In my youth, you would have been kicked in the ass, if you wore a Bayern shirt, because everybody knew they were
"something better". Players like Müller, Lahm, Neuer, or earlier guys like Giovane Elber, Pizarro or coach Jupp Heynches showed a much more down-to-earth or funny (Pizarro, Elber) behaviour, which is much more likable than the snobbishness of earlier days.