> I'd much rather my family be the one reaping its benefits when I die rather than some soulless corpo

Those aren't the only two options. If your copyright expired after a few years, your work would simply go into public domain, freely accessible to anyone. (The ones to "reap its benefits" at that point would be the general public.)

> Why?

The amount of money a single person spends throughout their lifetime generally orientates itself on the amount of money a single person earns throughout their lifetime. (We earn significantly more than 50 years ago, but we also spend a lot more, because our standards rose accordingly.)

If you expect your money to support the lives of multiple people (generations even), you are implying that your labour is worth multiple times as much as the labour of others. That is arrogant.

(I don't claim it should be actively prevented to make such large amounts of money. But we shouldn't legally limit people's access to literature just so a few authors can create a dynasty.)