re: #183 Dr Lizardo
The four films which really changed the way Hollywood makes - and markets - films all came out of the 70s.
Jaws.
Star Wars.
Superman.
Alien.
Those four films altered the Hollywood landscape and ushered in the era of the “event film”; the summer blockbuster, a pattern we still see almost four decades later.
The Exorcist.
(Sorry if already mentioned…I’m rushing to catch up)
EDIT: The Godfather.