This is really owed to the display technology. With prices of memory for a bit plain frame buffer in the astronomic regions, early computer displays were x/y di

This is really owed to the display technology. With prices of memory for a bit plain frame buffer in the astronomic regions, early computer displays were x/y displays, often just plotting single dots. So any visuals were generated on-the-fly. (Text was generally put out on another media, namely paper.) While Computer Space had a raster display, it generated its graphics also on-the-fly by means of circuitry. In both cases, displaying text was complicated and added another layer of complexity (and was also more time critical).