That became the case when it moved to Wembley permanently in 1974, the year of that Bremner/Keegan fracas but in the early 70s it was a case of who the FA could persuade to stage and take part in the match.
1973 - City 0 Burnley 1 - Burnley were second tier champions, City had a poor season. (should have been Liverpool v Sunderland)
1972 - Villa 0 City 1 - Villa were third tier champions, City the team who should have won the league but didn't. (should have been Derby v dirty Leeds)
1971 - Leicester 1 Liverpool 0 - Arsenal had won the League and Cup double. Liverpool were losing Cup finalists, Leicester second tier champions.