I think there's a lot of truth in what you say. Markets decline but they don't do so in an even way. I think younger players, who have the potential to last through this drop will hold value the highest.
Rennes, Brescia and Birmingham all have a model of having to sell to survive. We have been there too. I think in this situation that clubs will be really desperate to sell, and will find (say in this country) 4 of the orthodox top 6 teams are really hit in their ability to spend (and that's being conservative). It's a big drop.
I'll be honest, I don't think we will go quite as wild as the 3 names above. I think when we talk of under 18's, it's more unknown players, like we saw the lad at Barca under 17's. I can see more speculative punts, but probably not the sort of money required for the above. What I would say though, is if one of them was on our radar, in a position we require strengthening we could do that. I don't think Brands is going toby lots of quantity though, it will still be quite targetting looking at his 3 years here.
What happens with those 3 will be interested. I am seeing Koln have Corona Virus now, and it's hard to see that league restarting. We will all be hit. If Sancho doesn't leave, I'm not sure Dortmund are as flush as they maybe felt they were.