CRTs almost never show the entire frame at all. The phosphor decay on a typical television CRT is so rapid that by the time the beam hits the right-hand side of any given scanline, the left side is completely dark.

And unfortunately that motion clarity comes at a cost: flicker. Some people, like my sister, cannot bear that cost. She has photosensitive epilepsy, but even before that ripened into full-on seizures in her 20s she became profoundly uncomfortable playing video games, and never got truly into them until flat panels predominated. Even without photosensitive epilepsy, flicker can be annoyingly perceptible and cause eyestrain even if you don't consciously register it. Most of the motion blur mitigation strategies we see on panels, like black frame insertion, suffer from the same problems. The only way we'll come close to solving both problems at once is with very high speed panels, but until then I'll take a bit of blur, thank you.