Nah, I'm just stating my impressions. I think Dortmund is a very good example what's possible if you have a clear long term vision and execute it properly, but I don't care enough to be emotional about it. If you get Sancho, that's fine by me. It's just an interesting situation. A team featuring Sancho, Reyna, Haaland, Brandt, Moukoko and Bellingham could be genuinely world class a few years down the road. And it's a game theory scenario. If Sancho stays, Haaland is more likely to stay and so forth. But if one leaves.. Their strategy of developing young talents and growing that way is great, IMO, but at some point they have to transition. And I'm curious if they succeed in that at some point in the future (don't believe it'll happen with this crop of players tbh).
I think you're overrating Dortmund's ability to keep their players, both on a financial level as well as on a competitive one.
Dortmund is a "big" team but make no mistake that Sancho, Haaland, and probably Bellingham too does not see it as a final destination in their club careers. They go there because they don't want to sit on the bench for Manchester City, Real Madrid, Chelsea or Manchester United. I have no doubt that Dortmund knows this and accepts that they won't be able to keep them forever.
Most young talents go to Dortmund because they know that they give them opportunities. Once you outgrow the costume its best to move on, Dortmund will survive and keep developing young talents like they always have. Doesn't mean that they won't compete without a Sancho but rather that they will have more money to get the top talents in Europe.
Financially, they can't justify that type of transition and keeping players from moving against their will isn't going to further them as a club either.
If there is one summer where it makes sense to cash in on Jadon Sancho its this summer. The player has his eyes on a move away and he has just come off a record-breaking season.
Keeping him at the club could pose a big financial risk of not maximizing profit which is crucial in these times and Dortmund knows this. They also know what kind of players they have in their ranks to fill the hole that Jadon Sancho would leave in their squad.