I do believe the qualification was lost at the beginning with home draws against Ukraine and Greece.
There were obvious problems with injuries, and also some other bad team selections. I agree with the young players you mention and just would add a few others.
Denmark, began to shine at the start of the 80's with a blend of mature players with pery promising young ones who were barely in their twenties.
After Piontek I've watched as Johansson, Moller Nielsen and Morten Olsen have omited young guys in favor of veterans which means that players are lacking from international experience.
For example Bjarne Goldbaek or Peter Nielsen had most of their caps in their late twenties.
What was Bran Steen Nielsen doing at WC 02 in Japan, where Mads Jorgensen could have been included?...
Bo Henriksen was exposed in Euro 2000, and despite that he kept playing even in Euro 2004...
That king of things can´t continue to happen. I've used a clear example in this forum some other times. In 92 Sweden hosted the Euro, and thier starting CB's were Joakim Bjorklund and Patrik Andersson, just 21 at the moment. They were given the chance and came to shine internationally.
Regarding the NT. I admired Olsen as a sweeper, being one of the best of his generation (when he played as a SW) even after he was 30. Maybe he didn't get recognition because he is not dutch or german.
But I do believe he has made important team naming mistakes in the Qualifying rounds. But looking behind him I don't believe Michael LAudrup has the experience to manage the NT at this moment. In the future he surely can. If the DBU retains Olsen, I think he'll need better assistant coaches (instead of Bordinggard) a vert strong friendlies campaign for next year, a new project involving more young players anda discard those who'll be too old in two years) and realize he must have a variety of options, ecause you can't play the same way for 4 years.
If he decides to quit, the only danish coach with int'l experience is Ebbe Skovdahl (Portugal and Scotland) but I don't know about his abilities or style.
The other danish coaches have had more or less success in the Superliga.