In modern production, an army of underpaid, un-unionized visual effects contractors who pitch lowest bidder contracts to manually retouch basically every single

In modern production, an army of underpaid, un-unionized visual effects contractors who pitch lowest bidder contracts to manually retouch basically every single pixel in the film six times over is a fine price to pay for studios, while this method would require carefully planning everything ahead of time, proper scripting, and not being able to change scenes after shooting nearly as easily, and also probably involves hiring unionized labor by talented tradespeople who can say "naw that's a bad deal and a dumb idea".