"Fringe" in this case means "outside the Overton window", not "only implemented for a short fraction of the history of the human species". Otherwise we'd have to call suburban living and freedom of speech fringe ideas, because the 1st Amendment is only slightly younger than copyright itself and the formation of suburbs is still in living memory for a handful of 100-year-olds.

>>Partially because fringe people who want to change the law make terrible legal arguments

>No one has ever changed the law to benefit the rich, no sirree.

You followed this up with a link to America's mind-numbingly long copyright terms, so I would instead point out that none of those were extended by judicial fiat. Generally a "legal argument" means something argued in front of a judge about how the law is, rather than something argued to Congress about how the law ought to be. The reason why reformers make bad legal arguments is because they're trying to use the legal system to do an end-run around Congress, because the rich people already own Congress.

That being said, they also own the legal system indirectly. It's staffed by professionals who have a vested interest in a set of rich people paying them money. If SCOTUS said tomorrow that, say, 1A overturns the Copyright Clause, half the legal profession would be homeless by the day after.

Also, trademark as copyright is already precluded by the federal preemption clause of US copyright law; you specifically cannot cobble together other rights into something that looks and quacks like a copyright.