Yeah. After Euro 2004 Jaap Stam retired from International football. He wanted to focus on AC Milan and his family. However, Marco van Basten recently asked Stam if he wanted to return into the Dutch squad. Unfortunatly he refused. But after this summer, Stam will go back to Holland and will play for my favorite team AFC Ajax. Stam will play less matches because the Dutch Premier League contains less teams then the Italian Serie A and perhaps he will think of a comeback in the Dutch squad, but the chances are still going to be very small.
About the players you missed in the Dutch team: Roy Makaay is a great striker, but when he wears the beautiful orange shirt, he plays bad, because he isn't a ideal striker for the Dutch squad. Makaay didn't even made it into the last 33 players and I don't think he won't play for us in the next two years, because he has some serious competition for his place as second striker. His name is Klaas-Jan Huntelaar. He scored over 33 goals in the last season for Ajax and it was a big suprise when Van Basten called up Vennegoor for the last 23 instead of Huntelaar.
Reiziger also retired from International football since Euro 2004. He doesn't play well anymore the last years and he suffered a lot of injuries. These days he's just a subsitution at PSV Eindhoven. Although he said a couple of months ago that he still wants to play for the Dutch team, Van Basten did not gave him another chance because he isn't in top shape and he doesn't play full matches anymore.
Edgar Davids was in the early months of Van Basten's career at the Dutch team captain. But after he didn't played matches anymore at his club, Van Basten decided that Davids shouldn't belong into the Dutch squad until he found a new team. But after last summer, when Davids moves to the Spurs, he still didn't get his invitation for the squad, except for one useless last game against FYROM. Now it seems that Van Basten ignores Davids. I regret it, because he's still one of the best.
As for Clarence Seedorf. For the last two years, Seedorf is fully ignored by Van Basten, for an unkown reason. He plays well at AC Milan, but most of the people hate him because he played like **** a couple of recent games in the Dutch team and because he always misses penalty's. Maybe that's why Van Basten ignores Seedorf for over two years.
And as for Boudewijn Zenden and Boateng. Well, Zenden had a great season with Middlesbrough. But Van Basten was on the Dutch tour. He prefered players from the Dutch league like Van den Bergh, Babel and Bobson on his position. And he didn't wanted Zenden playing like a leftback of leftmidfielder because Zenden isn't a defender and as a midfielder he couldn't play in a 4-3-3. After Zenden went to Liverpool he suffered from diverse injuries and he didn't play all the time so he is forgotten.
George Boateng is a great player, but Van Basten simply prefered the young Wesley Sneijder for his position. Sneijder was at the moment in great shape (But he lost is somehow).