Here's where technology comes into play. The smaller the dot, the sharper the image. Sony developed a better way to do this. Moreover, less interference with the light coming to the screen seems to explain the noticeably brighter image associated with Sony's Trinitron tubes. Another Sony innovation, now seen in monitors from other companies, is the use of a single light gun.
Sharpness is also a factor of the focus of all three color elements.
Again, the result is sharper, brighter images. This is a matter of scan-rate. Notice that most manufacturers' monitors will support a higher resolution with a slower scan rate, but will recommend a lower resolution with a higher scan rate as optimum. This is the trade-off. Sony, obviously, has a strong presence in the monitor market.