Because you're telling a story, and I'm sure people fifty years ago would tell the same story differently if they were telling it to you today. Because the time is different. The film is the work of today's audience.
What you want to do is, you want to get away from people being afraid to show their work, which is the first thing, because they don't want to be shot down.
So much of it is the design of the shot or the motion of the character; it's the work you do so that it has the same things that are in the movie. In just a few frames it's got to communicate something clearly and dramatically.
And it's very hard to do this stuff too because there are so many effects movies being done, so many companies busy doing this work and the public just wants to see it. Good work is being done all over the world.
I think you've got to talk to the director, see the director's films and recognise that it's important that the work fits right in and see if as part of the movie.
It's harder for me to work on a Forrest Gump kind of movie, where everything is invisible.