This is a fundamental misunderstanding of what copyright is.
Copyright is a system designed to encourage the creations of work. It was not designed as a system to allow people to main perpetual control of their own art and work.
The original term of copyright was 14 years (with an optional 14 year extension). Why do you think the founder's believed that people "shouldn't be in control of their own art"?
You are "leaching" off thousands of people from history every moment. Using words and concepts they came up with, eating food from fields tamed and conquered by long dead people.
Rights exist as heuristics for making the world a better place, full of fulfilled happy people living meaningful lives. We benefit from the works of others and this is a good thing, it is our main advantage over creatures like the octopus.
