Sure, that example is a bit constructed and imo the death+50 years or 100 years are way too long, but I see value a) in the fact that artists need some time to finance their work and b) that some degree of inheritance is good.
(Self employed are in a complicated way in between)
Not that long; IIRC, the vast majority of the money made for most artistic works is received within the first decade after creation; the share of artistic works returning much after that compared to before is small.
Sure, the works you’ve heard of are often exceptions to this, but that's because you are vastly more likely to be aware of things way out in the successful tail end of the distribution.
While for some it is the long tail which makes it viable.
Even ignoring inheritance this is wrong, because you can sell it to someone who might outlive you, and spend the proceeds while you're still alive. The amount you can sell it for is going to be much less if there is substantial risk that the property goes away soon after the sale.
I don't think copyright needs to do double duty as life insurance and it is mostly not helpless widows that are benefitting from it.
The same rules that apply to a survivor's pension could apply to copyright, although I don't think that is a good solution myself - I think it will get messy with copyright transfers made in life, decisions made by owners/publishers/media/regulators that might de-prioritize the printing/marketing of that copyrighted material, etc. Even during the life the copyright creator, copyright rights are no substitute for a survivor's pension. In line with another answer below:
"What does the average person have to do to provide their family this kind of security? I don't think copyright needs to do double duty as life insurance and it is mostly not helpless widows [widowers] that are benefitting from it."