Manufacturers care about what their customers want, ie what sells. Most people would go for a thin screen that's easier to manage rather than a great big box. Also these days people want massive screen sizes and CRTs are just impossible to make large enough. We used to have a 32" widescreen CRT and that was a beast! I can't imagine the size and weight of a larger screen sized CRT. In the days when the average screen size was 21" you could get away with a CRT; these days they're just too impractical.