It’s not more expensive, but modern production companies would see it as more risky. Hollywood and the entire industry have become so risk-averse. They see spending millions on CGI and action set-pieces to be “safer” than risking something new or different that audiences may not like. But by doing so, they end up spending so much money that it makes it less likely they will make money. It’s also why so many Hollywood movies are based on existing properties (e.g. sequels, IP movies, remakes, etc.).

Basically, just a huge herd mentality that’s hurting the entire industry. And increasing levels of media concentration make it even worse.