Haha, too true, too true! Although, there were a few opening sequences that I noticed were absent, from some series I enjoy. Cowboy Bebop was represented, but I noticed Watanabe's other series Samurai Champloo was not-- perhaps because its opening sequence was quite different in approach from the cliché presented here. Same with Ghost in the Shell: Stand Alone Complex. Perhaps I missed a clip pulled from the second season (though I doubt it), but I'm certain the first season opening was not here-- it would have been quite noticeable, because the first season opening was completely produced using 3D computer animation, and no traditional anime at all. Lastly, I didn't see the late Satoshi Kon's Paranoia Agent (a greatly underrated series), likely because it too was a bit outside the usual anime tropes. I think some anime artists acknowledge there's a stylistic rut into which they've been pigeonholed, and luckily there are those who react against it to try to expand their medium beyond the preconceptions.
Point is, it's not every anime opening ever made-- but pretty darn close. 