> 0 years is more than enough time to profit from creative works. Are we as a society really saying that 75+ years is how much time people ought to be profiting from creative works? An absurd proposition in almost any other industry or pursuit.
How is it any more absurd than a trademark? Why should someone be able to write and sell a book about Harry Potter but not sell their own Iphone?
The purposes of those concepts are totally different.
The purpose of trademarks is customer safety. If it wasn't illegal to infringe trademarks, it would be much easier to distribute fake products, and companies would have less incentive to build their brand on quality.
The motivation for copyright is similar in that it exists to incentivize beneficial behavior (creating valuable works). But it's different because it also limits the distribution of the works. If this "cost" is too high, there is no economical sense in having so long copyright.
Trademarks are not intrinsically valuable (to society). Limiting their use has no cost.
How is it any more absurd than a trademark? Why should someone be able to write and sell a book about Harry Potter but not sell their own Iphone?