The major studios use cloud services all the time. For example, Paramount uses AWS. Disney has its own internal cloud system but also uses a combination of external clouds like AWS.
The resistance to cloud services is based on preventing leaks, not opposition to technology.
And in specific response to your comment: Netflix's "technology" is just a content management system. They're just reinventing a wheel that many of their competitors already use and bragging about something that Disney, Paramount, etc., did over a decade ago when they began embracing digital-first production.
“major studios do use some cloud services” is not the issue. The problem being addressed is that the “script to screen” process is typically an antiquated mishmash of offline-first vendors. Netflix reinvented that with a cloud-first process.
“Digital-first production” can mean lots of things, so when you say Disney, Paramount, etc did this a decade ago, you’ll have to be more specific. Do you mean an end to end digital process? That’s not what this is about. Have you worked on a Netflix production? It’s night and day different from the studios you mentioned.