Things can always be copyrighted or copied. The idea that could work is making things easier for the user and also tutelage. Like MM to oversee and remove content that is copy of others, standalone Indies being licensed and the like.
I'm not really talking about copyrighting. I recall MM talking about people being able to make games and publish them on PSN and they simply said 'it's more complicated than you think'. I wouldn't know the hurdles involved, I just know they exist (at the moment). Something tells me though, because of what I said about creating usable content, a little dragging of the heals is likely to take place. I can't blame them for doing that because, like I said, it's imperative that quality content is there for all creators to use. Once the floodgates open, lots of people will want a piece of the pie, even if their content isn't up to snuff. I would imagine THAT'S the can of worms MM and Sony fear more than anything. The last thing they want to do is unnecessarily bring discontent into the community.
The PS5 Exists.