It wouldn't. If a music studio needs to wait 4 years to not have to pay any royalties at all, then the song would be recorded (copyright created) and the music groups would just wait 4 years and then start playing it on radio stations.

It needs to be something like 12 + 12 or 20 + 20, or even 20 + infinitely continuable for a gradually increasing cost. It still has the potential issue of waiting out that 24 to 40 years; but companies are less likely to do that, when a few years is basically nothing.

It's been 2 years since covid started, for example.