CRT's may have a DVI input, but they dont use the digital signal contained. if you look at the
DVI cable, you'll see that the most common format is DVI-I. Look at the picture, you'll see pins on both DVI-I and DVI-D cables, but the very rightmost part is different.
DVI-D sends only the digital signal via the bank of pins on the left. DVI-I sends the same digital signal through those pins, but also sends an analog signal through the 4 pins on teh right.
Correct me if im wrong, but every CRT with DVI has used the analog signal.
Also, this is how ATI's included DVI->analog converter works. There are no active components to convert teh digital signal to analog, it just matches up the pins on one end to the appropriate pins on the other end.