I'm thinking most of the people involved in scenes with only a handful of extras are doing other things in the film and are just asked to stand in here and there.
As much as I'd think it would be neat to see the workings of the movie making process*, I wouldn't want to have to stand around for hours in a large group of people with my two stale donuts and styrofoam cup of coffee and be a random face in the crowd in the larger extras scenes.
* I'd much rather see a band cut an album but I don't think there is much roam for random bystanders in those circumstances. As a happy medium, I have been close to the stage in a concert video although I've never been able to find myself in the crowd.
I know people who have done it for fun more than for a bit of cash. One guy was a background zombie in the original Night of the Living Dead. Another who had to lay on the ground covered with fake blood for hours, lol. I don't feel sorry for them, it was a interesting experience for them.
A retired friend from my job has appeared in the background crowds of a lot of movies. Extras usually get a little bit of pay, a nice free lunch and the chance to see big stars and movie production up close. Seems like a pretty cool deal to me!
IN MY LATE TEENS I DID SOME EXTRA STUFF...BIGGEST THING I APPEARED IN THAT YOU COULD MAKE ME OUT IN WAS A NATIONAL COMMERCIAL WITH KEN GRIFFEY JR...I ACTUALLY ATE LUNCH WITH THE MAN AND LATER HE HIT A BUNCH OF BALLS OVER THE WALL AND THEN SIGNED ONE OF THEM FOR ME. NOEMOJI
I actually considered doing "background" work when I was unemployed and on the verge of going back to college, but there was no work as an extra to be had in the region where I lived and I couldn't afford to move to Los Angeles or Vancouver where the movies are shot. But I found the idea of picking up a bit of no-skill work here and there to be appealing, as well as the idea of seeing how movies are shot, and the idea of being paid to sit around while more important people argued. But oh well, I had to get a real job, but still. Maybe I'll look into extra-ing again, when I retire.
Did you know there used to be such a thing as a "dress extra", someone whose job it was to show up in fancy clothes whenever filmmakers needed to fill a party or a fancy theater audience? Back in the day, they worked for the film studios and weren't actors and didn't aspire to act, they were full-time extras whose career was based on their ability to show up in an infinite variety of formal or semi-formal clothing, They were considered to be the highest-status form of Extra, and reportedly looked down on regular extras.
If you're referring to the "dress extras", that wasn't just renting a crowd - it was renting an UPSCALE crowd! A crowd that could pass as a Broadway opening night crowd!
What are you talking about? It's a job, and an easy one at that. Also, if you have aspirations of becoming an actual actor, starting out as an extra could help you get your foot in the door. For example:
Yeah, there's such a thing as unsung heroes, the people who work backstage, behind the scenes. I once went to the estate sale of some old guy living alone who had died. It turned out to be somewhat of a mind blowing revelation. I learned he had been some obscure worker on the sets of many of John Wayne's movies and he had worshiped The Duke. His entire home had basically become a shrine to the actor. It was fascinating, the stuff he had accumulated.