Let's say you're a musician in your free time and you wrote a pretty catchy song that you post to your web-site. A coke marketing guy hears it and thinks it would make a great song for an advert. They use the song and it's tremendously successful, people love it and coke has made millions because of it. People refer to it as "that coke song" (your name is in the fine print since in our imaginary world there is still some vague regulation on attribution, in a world with no ip laws at all Coke could claim authorship). In the end, despite it being your work, you receive neither money nor fame from it.
Anyone who has done any sort of creative work knows that larger corporations aren't typically the best at producing it, a world without ip laws would ultimately mean that this issue could simply be overcome through easy exploitation.
