Revenue is used because this industry is notorious for “Hollywood accounting” to avoid having any actual profits to avoid residuals based on net.
Some of the biggesr blockbusters of all time are, thanks to Hollywood accounting, net losers. Forrest Gump is a classic example: it made almost a billion dollars in revenue vs a $55 million budget. But thanks to tax evasion techniques the movie is actually a huge financial loser on paper, losing more than $65 million if you look at net.
You can’t trust non-workers, who exist entirely off the wealth they can cheat out of workers, to be honest.
So that is why gross revenue is used in Hollywood.
Edit: to add on to that Gump example, the author was supposed to be paid based on net. He got totally fucked which is why no sequel was made. His IP created a billion+ dollars out of thin air, but blood sucking capitalist parasites leech it all away with tax evasion.