There are a lot of people who wish "Damn, wish I could've made that." whenever they enjoy a popular piece of media.
This trope seem to fulfill that wish, I believe.
There's a movie about that, right? The world suddenly forgot that the Beetles ever existed, except for the protagonist. So, he began singing their songs as if he composed it himself and got famous for it.
I've seen this exact trope in plenty of Isekai as well. Some used it to make the...