Yeah I'm not claiming they are good enough to take a shot at winning a big competition like the Euro or WC but qualifying at least should not be this big of a problem.
Robben is not done, he's still one of the most important players at Bayern and undoubtedly world class. Sneijder, you can argue about, I still see quality in him when he plays for the NT. Wijnaldum is doing very well at Liverpool, same goes for players like Strootman at Roma, De Vrij & perhaps Hoedt at Lazio, Dost at Sporting etc. Maybe they're not world class but the level at which they play at their respective clubs is much much higher than the level they reach for the NT.
Memphis is doing very well at Lyon, scoring 5 goals in his first 7 games. He set the league on fire when he was at PSV and while you might not take the Eredevisie seriously ( I don't really take it serious either), as someone who watches it weekly, I know talent when I see it, and Memphis is a big talent. 1 and a half failed season at United is not going to change my opinion on him when others have failed at United aswell and blossomed after they left (Di Maria, Chicharito etc).
They went from being 3rd in WC 2014 under van Gaal to not even qualifying for Euro 2016 (which was the Euro with the most teams in history) and now are in danger of qualifying for WC 2018 under Hiddink/Blind who have made bad decision after bad decisions. I believe Dutch Football is not what it's used to be but I don't believe it's as bad as it is now.