[dragonwriter]

> The reason why it was "life plus X years" was to provide a means for the family if the creator had an untimely death.

Doesn't make any sense; a fixed term copyright as is used for corporate-author works (currently 90 years) does that just as well.

All a “Life plus X” term for, in terms of expected to benefit, is give decreasing expected copyright term as your age increases (well, as remaining life expectancy given known facts decreases, more precisely.)

I suspect “Life plus” was more about eliminating disputes about creation date for individually-authored works that aren't immediately published, not about what it provides to author’s families. With a “Life plus” term, creation dates become immaterial in computing the end of the copyright term, if you know who the author is then, once their death date is known, expiration of all copyrights is known even if the exact creation date of some works is not known.