I agree that the movie metrics are heavily skewed to make new releases look good. When "Gone with the wind" started to sell its 200M tickets, the US had 132M inhabitants (https://www.census.gov/history/www/through_the_decades/fast_facts/1940_fast_facts.html). That's just 40% of the 333M the US has today (https://en.wikipedia.org/wiki/Demographics_of_the_United_States). So I think I think older ticket sales are more valuable than newer ones because today there much more people who can buy tickets.