No, it really isn't. The person who built that piece of furniture does not deserve an overall control of the design for the person's lifespan + 70 years. There

No, it really isn't. The person who built that piece of furniture does not deserve an overall control of the design for the person's lifespan + 70 years. There is not a single rational justification for the 100+ year protection, nor should the society protect the few's livelihood when it can benefit everyone once the protection expires. Switch your scenario the other way around because the reality is, the laws benefit larger companies more than the small indies. A lot of people in US didn't patent their ideas because it cost money to even start the patent process with a lawyer (you have to pay to research prior arts and so on). Your scenario switch: A company built and patent that same furniture design and you as a small time designer can never sell that design with your own improvements on top of it for practically over 100 years. You cannot improve on a basic copyright unless you have permission. You can end up in a scenario where a massive amount of copyrighted designs are owned by a single company and there is nothing anyone can do for 100+ years. The original purpose of the copyright (in US) was to push the society forward by promoting the arts and science by protecting the creator's work for a limited period of time, so everyone's motivated to create original stuff. Society suffers from extended protected terms. I'm okay with protecting the person's work for 10-20 years once the work is done, but there is no justification for 100+ years. I don't care if that person goes out of work in 20 years, it's not up to us to protect him for life. In this age with ~7 billion of people, the right of one single person (or one company) over hundreds of millions of folks is no longer sane.