Receiving money for something you wrote 1 week ago doesn't encourage you to write more. It's the knowledge that you will receive money for next thing you wrote that incentivizes you to write more. And a 50 year payout should obviously provide more incentive than a 6 month payout.

There's going to be a point of diminishing return where adding extra years doesn't provide enough extra incentive to justify the cost, but I haven't seen any convincing evidence that 50 years is over that threshold.

The same holds true for copyright extending past the author's lifetime. Especially if an author is older, the knowledge that their children will benefit is certainly an incentive.

> Twenty-five percent who went to the library learned about political or cultural organizations or leisure activities taking place in the local community. More than 20% went to the library with friends or colleagues to work together on a common assignment or a leisure activity. Seventeen percent used the Internet at the library to contact friends via e-mail, to chat, or to participate in discussion groups, etc. Sixteen percent used the library to learn more about local matters, social or political issues, etc., that they are involved in. Fourteen percent participated in organized meetings, such as author's nights, lectures, meetings with politicians, etc. Ten percent used the library as a place to meet family or friends before going together to the movies, into the city, to do shopping, etc. (p.19)

https://www.ala.org/tools/research/librariesmatter/use-publi...