The problem, as I see it, is unfocused storytelling.

It starts with a good screenplay that is focused, concise, and well paced. Shoot more than you need to tell the story, then edit out everything that's not 100% necessary. Be lean and purposeful in your story. A great screenplay will service everything in the story with great economy. Great scenes will serve two or more purposes, develop the story, and - when they're really great - make you lose all sense of time.

Many films are full of sprawling superfluous plots that don't amount to much. I feel this most during certain blockbuster films that are packed to the gills with spectacular set pieces, have three separate "emotional" climaxes, and somehow fail to stick the landing. When these elements are poorly balanced or overcooked they feel like a slog.

I've never heard Demolition Man described as a grownup movie before.

If a movie is well made then it is as long or as short as it needs to be. If it isn't then it's not.

Movies you watch in theatres are one thing. It’s uncomfortable, you can’t pause it, you can’t contemplate it, there’s people all around you. It’s not an immersive experience despite a big screen.

So not all movies are best seen in a theatre. And the ones that aren’t are probably not long enough.

Physical media use to account for half of a films eventual gross. Some films even did better. See every cult classic (Office Space comes to mind easily).

When you’re making films that have to be produced for second run distribution on physical media they had to fit on VHS cassette.

Studio VHS production ended in 2006. Netflix VOD began in 2007. At that point the length of your film stopped mattering. It took a few more years for studios and directors to realize it, but that was the actual end of economic constraints.