If you're old enough, then the first word processing program you ever used was probably on a screen 640x480 pixels or smaller, didn't support internationalization, couldn't provide true WYSIWYG to match output between the screen and a printer, and couldn't render fonts with anti-aliasing. Which of these features would you like to drop to reduce the size?
Everyone loves "tight" programs until they realize what they have to give up to make it work.