I believe a portion of the cost of blank tapes was allocated to recording artists to cover this costs, so perhaps it wasn't entirely free...

So which one is it: was music free or not?

When an ad comes onto one radio station, you switch to another without ads. Redundant array of independent radio stations. Advertising is damage. So advertisers coalesce their ad timing, so the damage happens on all independent channels simultaneously, so you turn off the radio for several minutes, maybe switching to Pandora or another stream.

When Youtube plays ads, you mute it and goto another tab, and keep watching a different video. When the ad is done (such nice ads for telling you their duration), you simply return to the tab and watch your content.

There's always another service that's looking to hook you before they advertise. So you can just switch between them.