That article has a huge misunderstanding when it comes to ghosting. In normal CRT TVs or monitors you could not see the previous frame at all.

The whole frame, no. But due to the persistence of phosphors, any pixel which weren't re-excited in a replacement frame would have some amount of "ghosting" while the phosphors "cool down" from the previous frame. The effect is more pronounced on black backgrounds, and nonexistent on white backgrounds, with other colors being heavily dependent on the contents of previous frames. Higher-quality CRTs also tended to have less persistence (my VT 520, for example, has virtually no visible persistence).