You need filming equipment, a good script, stage infrastructure, well-performing or/and good-looking actors, repetition until they get it right, sound-tracks (with composers, interpreters, instruments & instrument people), editing, post-processing and maybe animation/special effects.

And it's an industry where profits are made at the high end of the market (you'd rather pay Tom Cruise $100 millions for the statistical guarantee of $200+ millions in Mission Impossible box-office openings rather than medium-quality people for no guarantee at all).

You can attack script-writing with software, or replace actors with computer animation done by software engineers, but you end up with poor low-end results or even more expensive budgets (that only make sense for computer-animated fans, see Toy Story).

The attack vector implied by pg was not necessary to make film-making cheaper but rather to make entertainment better and probably different. E.g.: video games took off in the last two decades, and their business model worked because every time you play a game you get at least slightly a different entertaining experience without any additional costs from the producers.