At least in the US, we have a lifetime for exclusive rights, at which point the material moves into the public domain. It really seems like a good system to me.

It's not a good system to have it be 50 years past the death of the creator. Having access to content in public domain has historically caused art to flourish by serving as a base for creators to build off of. But for the past few decades companies have been plundering from public domain while not contributing anything back.

Our original copyright system in the US gave a baseline 17 years of copyright, with an additional 17 years extension that you could apply to. 34 years is a perfectly fair span of time to get value out of your creation because nobody is going to wait that long to get access to art they want. But it also ensured that the public domain continually had new content added that wasn't completely antiquated. This is the system we should be pushing to return to.