What about things they did 6 months ago? The argument is whether music should be copyrightable at all, not whether 100-year copyright terms are reasonable.
Why indeed? We don't pay for food each time we reap the benefits of the nutrition it provided down the line. Weightlifters don't pay royalties to protein powder companies. It could be argued that artists could also be expected to not be paid beyond the initial creation of a work. It would be a very different world to be sure, but it's not a given that it would be a worse world.
No. There are two arguments. Whether music should be copyrightable at all is settled (though a fringe continues to argue it). That means that the second argument, whether 100-year copyright terms are reasonable, is in fact the main argument at this time.
