The "One-Hit-Wonder" Rule of Copyright Compensation

From a podcast listener named Ed Morgan, in response to our recent episode called “Who Owns the Words That Come Out of Your Mouth?”:

While listening to your podcast on British copyright laws I was thinking you missed an important point. If you want to keep content providers producing, you can’t pay them too much. It’s what I call the “one-hit-wonder” rule. If a single piece of copyrighted work is so popular that fair compensation to the creator eliminates the incentive for the copyright owner to ever produce anything else. The same could apply to the creator’s heirs. Would Churchill’s descendants produce new and more content if they were not getting paid for the work their ancestor did?

I think Ed’s observation is more relevant for the heirs than the creator him/herself. Thoughts?