In the past, seating spaces were often installed in banks of straight rows, and the best theatres had sloped floors or a balcony. Usually, chairs were all the same size (width) which hurt sightlines. In addition, little consideration was given to persons with mobility issues. Access to exits was also limited.
Historic safety code for conventional layouts specified there could be a maximum of 14 chairs between legal aisles, and a maximum of 7 chairs between an aisle and wall. Rows had to provide clear passage of 12".
This type of layout is still used today from time to time, but often in very small spaces. Modern design and construction techniques and an awareness of patron comfort make this type of layout the exception and not the norm.