That only stops them dividing the prize further, it doesn't stop them awarding for work which in fact took a great many people - only some must be highlighted. I'd guess almost all the modern Physics and Chemistry has a long trail of people who were crucial but didn't get the prize, some of whom the actual winners would cite if asked, and for others they'd probably say "Look it's a cast of thousands, if I forgot to mention you I apologise" or similar.

When a movie wins the Best Picture Oscar, only a few people actually get the physical object, but of course almost all modern movies (especially those likely to get Best Picture) have huge numbers of people involved and even the Producers are too numerous to all get up on stage for some movies. To fix this, a movie that's a plausible Best Picture contender will ensure that it deliberately highlights some of its Producers in the credits as the people to whom such a prize would be awarded. Take "Barbie". Margot Robbie is on that short list of Producers who'd have got the actual statuette if they win Best Picture, in the end Oppenheimer won.