Yeah they just make the big bucks off of it. And at the same time while they rake in that fat stacks it is just another reason for customers to buy less physical Media which is Ironic because it is where Indies are starting to actually make a decent living.
The artists make approximately diddly-squat if no one listens to them. Note that they’re not forced into this channel - if they can make a better go of things without it, power to them.
You’re comparing record sales to radio play. Two totally different things, and the former is typically driven by the latter. Also, there is no way indies are making more on physical disc sales, after costs, than they’d make selling the same content digitally.