Hi!

This is because the rotational speed of the disc is so high
compared to CD, that a significant drag wind builds up under the disc,
which
keeps the lens blown clean of dust deposits.

That's not always true. Compared to a simple audio CD player, you're right.
However, any computer CD-ROM drive, CD burner, or even a CD player designed
to use digital audio extraction will spin as fast or much faster than a DVD
playback drive.

Besides, doesn't moving more air across the pickup just result in more
stubborn dust appearing? :-)

William