I'll agree with your premise that more movies being made means that more movies that are likely to be good, but I doubt this has anything to do with the real reason they expanded the nominations. No industry is more self-congratulatory than the entertainment industry. We could tick off the names of different award shows until the music played us off stage. Awards shows make money not just for the hosts but for every movie that gets to say it was nominated. Now twice as many movies will get to say they were nominated in their ads. By the way, this sentence is a crime against redundancy, "At the time it came out, Thriller dominated record sales like nothing before or since."