>>211892612 (OP)Cinemas make their money from concessions, but movie viewership is in the tank. So, what do? How about you show a movie several weeks before release for $5 per ticket (keeping $0 of that, because studios), and they pack the entire screen, and 90% of the audience will also spend $10+ each on concessions that cost them 10 cents to produce. They'll probably make $2,500 per screen from doing that. So they do.
And the studio go for it because they get $1,500 from ticket sales for that same screening (a lot more than they will from the average screening), and thousands of people who will go on boast to their friends and colleagues about how they saw an advanced screening of a movie and it was great, which means more ticket sales.