It gets better, because all the money they "lost" on a movie they can also write off. Oops, we didn't make any money this year because we put out 10 billion dollar movies and only made 10 million at the box office. Tax break please!

For all we know, they're literally just passing massive checks in a circle to one another to say "yes, it says right here in our bank records that we spent a combined $100,000,000", meanwhile only 25% actually goes into the production, and they pocket the rest.

That would be illegal and easily discovered

But you could pay $10M to hire another company to do the sound mixing. They might spend $500k to do the work. You might also be the owner of that company, and the money ends up back in your pocket...And that's not embezzlement or a kickback, because that's what it's called when poor people do it