Borussia Dortmund is a team that develops enormous potential without ever worrying about making it perform at its best for its club. If they didn't only think about profiting from the various players they sell they would now find themselves with a formidable squad made up of truly formidable players and with more than concrete possibilities of being able to compete on every front.
I think one of the reasons Borussia Dortmund have these goals is because Bayern Munich invests a huge amount of money in developing their squad. And competing with a team like Bayern is incredibly difficult. So rather than waste their energy competing with Bayern, they prefer to spend it on finding new young talent and then selling them. I can't blame them for that, if they earn a huge amount of money and still continue to play in the Champions League, then I think that strategy is also very good.
I think what you mean is that they should be realistic and accept the situation without making any effort. If you look at the situation from above, you see Bayern's hegemony, but from a fairer perspective, you also need to consider the possibility of winning the championship. Borussia Dortmund should build a squad accordingly. They might even beat Bayern, we can't know for sure.
Sometimes people also forget that football isn’t always about having big players in a club before the club gets to win a trophy, what matters most is teams spirit and the willingness of players to compete and fight together no matter the limited resources available to them. We have seen what happened in the league 2 or 3 seasons ago when Bayern Leverkusen won the league in style it was a total dominance in Bundesliga, winning it unbeaten throughout the season. These other clubs seem to be given up too easily even before the season starts, they are already tipping Bayern Munich to win the title which is a wrong mentality, I think this other clubs are giving Bayern Munich too much respect than they deserve and that’s why they can’t compete for the title.