So apparently, both Seasons 7 and 8 were originally intended to be the final season:
Season 7 was intended to be the last because of George's engagement arc: the season was going to end with George and Susan actually getting married and moving away, thus causing Jerry, Kramer, and Elaine's worlds to come crashing down, prompting them to go their separate ways as well, and all would be wrong with the world.
Season 8 was intended to be the last, hence the checkered logo that season that was supposed to represent the finish line.
Season 7 was intended to be the last because of George's engagement arc: the season was going to end with George and Susan actually getting married and moving away, thus causing Jerry, Kramer, and Elaine's worlds to come crashing down, prompting them to go their separate ways as well, and all would be wrong with the world.
Season 8 was intended to be the last, hence the checkered logo that season that was supposed to represent the finish line.