Everyone else gets paid for their work when they do it. They can even invest the money like everyone else. When you've hit it big with a creative work you are set for life. But when I build a house for you, I get paid once.
This is fine for transactional work, where it's very clear - you do/make something and sell it, perhaps a carpenter selling a table or whatever.
It completely fails if, for example, an author spends 4 years unpaid writing their latest book, and after the first copy is sold anybody is free to duplicate the words from that book without giving the author a penny for that work. One of the specific reasons for copyright is to ensure that the author is granted exclusivity over sale of the works, such that they can earn a fair wage to compensate for the 4 years of their life without any income at all. How us it unfair that if that author lives another 50 years and people are happy paying for the book for the next 50 years, the author should continue receiving money for it, rather than just some unrelated party whose only skill is being able to scan and reprint the book for basically the cost of the paper?
It's also fair to allow copyright after the author's death, because their children also should be allowed to benefit from their parent's work too. In most families, the parents want to pass on a legacy to their children. Why should an author be any different? Or are you saying if someone owned property that provided a monthly rental income, on their death the children shouldn't be allowed to inherit that property or the income stream?
If you say that the parent needs to earn all the income from the novel themselves and only that can be passed to the children, what if someone has spent 4 years writing a novel, and is killed in a traffic accident a day after launch day? Should their children not be allowed to profit from their parent's work just because they died before the income stream was realised? What about the 4 years of hardship the entire family endured?
Corporations just extend this thinking, because legally a corporation is considered to be a legal person. If you're making a film that requires lots of capital and many participants, there's a lot of investment in that production. In this case, it makes sense that the individual artists sign over their rights to the work they do for a salary to the company (if they don't like a paid job, they can always go and create their own works or set up their own company, etc) and equally, the investors need some time to recoup the investment they made. If we didn't permit this, then simply put, the vast majority of films would never have existed. Society would be far worse off.