If they are so concerned that struggling artists should receive revenue, they should legislate existing contracts out of existence and impose that all artists must receive at least 50% of all gross income, for the problem isn't that musicians should continue to receive returns until their grandchildren grow up, but that they receive only a pittance even now, when the copyright is in place.
To put it another way, copyright doesn't help the artist much if the contract doesn't allow the artist a good return, and an extension of time can only help the industry labels.