If this is true, why is that quality LCD and PDP show more derails in a dark scene then a CRT (in low light conductions)?
Contrast ratio is only one factor in overall picture quality. Color decoding, video processing (and associated video bandwidth), and resolvable resolution are others. With CRTs, convergence has a significant impact on the resolution you get.
Most CRT displays are not converged properly. The guns move slightly out of alignment during shipping -- and over time after setup, due to gravity -- and few people know how to fully converge their displays. Further, modern consumer CRT TVs use 7" CRTs, which -- even when properly converged -- typically limit resolvable resolution to the range of 1200x900 to 1400x1000. Out of the box, very few CRT TVs will deliver anything close to that. CRT TVs also use interlaced display for high-definition signals; modern CRT displays cannot display 720p signals without lossy conversion to 1080i or 540p.
Comparing 1080i and [properly deinterlaced] 1080p signals, side-by-side, on displays that can fully resolve those resolutions (which CRT TVs cannot), the human eye will perceive a more stable and detailed image from the progressive signal, even when the source is 1080i video. On true 1080p24 sources, like HD-DVD and Blu-ray, as well as movies and episodic programming on CBS, NBC, HBO, and Hdnet, 1080i CRTs cannot reproduce the full information in the picture signal.
As you know, we have plasmas and LCDs available with 1920x1080p resolution.