Copyright is traditionally an area of law that has been served by moderation. The government offers some protection to creators, but not absolute rights. For instance, songwriters have a right to receive royalties when someone else records and distributes their song, but they don't have the right (in the US) to set the price of that royalty, or to veto a particular artist covering their song. It's a balancing act.

On the one side, if you don't have copyright at all, it severely limits the ability of creators to monetize easily copied works. This became a problem with the printing press and copying has only gotten easier as technology has progressed.

On the other side, there are a number of problems with granting an absolute, indefinite copyright. One is that you stifle the creation of derivative works. Another is that obscure works can easily fall out of print and be lost forever. A larger philosophical concern is whether corporations should be allowed to hold control over the shared cultural heritage of a society long after the actual creators have died.

Almost everyone sees the need for some kind of compromise here. Personally, Canada's life+50 years sounds pretty reasonable to me.