Of all those who went to Gatsby’s parties, none came to his funeral, except for Owl Eyes, a character who’d marveled at all the books Gatsby owned. Only Nick, Owl Eyes, and Gatsby’s father - showing up grief-stricken after reading everything in the paper - are at the funeral.
The theme of the book revolves around this scene: Fitzgerald’s beliefs that you can count on individuals, but never humanity. People - speaking generally - are terrible. Nick couldn’t even count on Jordan. The masses were conspicuously absent. Daisy didn’t come to Gatsby’s funeral. The only people who showed up were Gatsby’s friend and neighbor; a man who’d been to one party, looked at some books and crashed a car; and a father Gatsby hadn’t seen in years. Fitzgerald’s perspective pervades here (a realistic perspective if one is a pessimist, a pessimistic perspective if one is a realist). This scene is paramount in illustrating Fitzgerald’s outlook. So, naturally, the 2013 movie removes the funeral entirely.
There is Nick trying to get through to people, yes, and coming up empty. But that’s it. Now, this version of the movie did include Owl Eyes, which the 1974 version can’t claim, so it must at least include the pay-off of his character’s existence, right?