I completely agree with you that 20ish years is plenty before a work enters public domain. The original 1790 statute which had a default period of 14 years was also plenty.
However, I think there are some things overlooked in your arguments...
It sounds plenty fucking fair. Architects & engineers don't get paid royalties for years & years on work we did ages ago.
That's because you have a choice to get paid up-front. Most artists/creators don't. If someone offered you a contract: "Hey -- you can design my building for me, and I'll give you X% of the rents for the next Y years, but I'll pay you nothing now," would you do it? What if the building was in the middle of nowhere in a completely untested market? What if your design was also very unconventional and you didn't even know if it would work?
Those are the kinds of things a novelist or even a non-fiction author, say, has to deal with all the time. They invest their time and effort spending months or perhaps years generating a work, often with no money up-front. And unless they're an established author, they're often breaking new ground, perhaps trying out something new which may or may not sell well.
I suspect most architects and engineers here wouldn't take such a risky deal. They'd prefer to actually get paid when they do their work, as do most people. Most creators take much bigger risks in the hope that MAYBE some day down the line they might recoup their expenses and time.
And -- of course -- the vast majority DON'T. For every creator who makes millions of dollars off of their books or songs or screenplays or whatever, there are thousands of creators who never really make a profit. But they try anyway, and maybe they get something back.
We certainly don't continue to get paid after we're dead.
I don't know why everyone is so obsessed with deaths of authors.
Look -- copyright is broken, but it's effectively a contract between creators and the public. If you signed onto a deal like I offered you above, where you got no money up-front, but I said you'd get a share of the rents on the building you designed for 20 years, that contract generally wouldn't void at your death. The rents would be paid to your estate or your heirs for the original term of 20 years.
Why should it be any different? The few creators who do actually make money often have kids to feed. If I spent a year writing a novel and with my family suffering without enough money expecting X years of possible revenue from my novel, why should they not get the expected years of revenue if I drop dead from a heart attack the minute after my book is published? Copyright terms should be fixed and short -- whatever they are. The death of the artist is irrelevant.
And if we fuck up, things fall apart. People can get hurt. People can die. If a screenwriter fucks up, nothing of any consequence happens.
Not sure what this has to do with anything. Are you saying that we shouldn't pay anyone anything if they don't do something "essential" enough or something? Why the heck do we pay sports players or actors or whatever? Most people spend significant portions of their days listening to music, watching TV, etc. Just because something is viewed by you as "entertainment" or something doesn't mean that it isn't hugely important to you or society -- and if we don't have a system that rewards creators, art gets worse. Good artists choose to do something else with their time. And there are also writers who contribute significantly to new ideas, knowledge, etc. -- if these people won't get compensation, they may not choose to do it. That's potentially "somethign of consequence" happening.
If you did the work 20 years ago, tough shit. Welcome to the world of everybody else.
Again, I think most artists/creators would LOVE to take a deal like most people and get paid up-front. But that's not generally an option, and it's not the way we seem to do things in our culture. The only people who can demand significant compensation up-front (commissions, book contracts, etc.) are generally the people who will already be guaranteed to get a significant return anyway. For artists who do things that aren't as high-profile or are less popular, they take big gambles. If they do succeed, they should be appropriately compensated -- otherwise, why the heck should anyone spend months or years of their time creating quality intellectual works?