Its more due to regional Copyright issues. For instance the Titans live action show is available on Netflix in other countries..but is only available on the DC Universe streaming service in the states. I can give better examples when I get home and can sign in.
Oh, I realise that. For instance Star Trek Discovery is on Netflix over here. I thought it was partially due to international broadcasting rights coupled with the fact DC Streaming/CBS All Access/Hulu are only available in America.
But the multiple streaming services is more an issue for TV shows than movies. If you o ly have Netflix plenty of Rock based movies on there for you to watch.