Exactly, it's all about money. Producing compelling movies cost huge sums of money. A lot of that goes in to advertising too.
If there's no return on your time and effort (and money) to make a movie, then it's hard to justify doing it. At least on youtube, creating content doesn't cost much more than your time.
I've been trying to think of where movies fit in in a "no DRM, everything is free" society. At least with free software, you can get paid to develop and maintain it. With music, if you release it for free, you can still make lots of revenue through concerts and merchandise. But movies? Maybe crowd-sourcing could be an option, but I can't see many people being willing to do that (except in rare cases where it has happened to bring back a beloved franchise or something).
Really the only way to make money from movies is by releasing them in the theatre, or on paid DRM streaming services like Netflix, or free DRM services with ads