People are scratching the surface here but not getting the whole reason. The license is because the owner can do whatever they want with the product, including sell it, or alter it. For art this means they could change a movie to say something really nasty, or use parts of it in their own stuff. Also the license allows an artist to say ‘these people can’t use this at this place no matter what they pay’.
For software it’s more important because altering the product can break things, and then people might act like it’s the original products fault. Someone might even do this on purpose. Or they might take the product, and change it around into something else, and try to sell their new thing, this is not allowed either. Also you are not allowed to use several copies of the same software at once, you have to buy as many as you are using, this is how they make money.
TLDR you get a license instead of ownership because when you ‘buy’ a copy of a product you are only allowed to use it as intended. They can’t tell you what to do with your own stuff but since you’re just using their stuff, they can.
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