I don’t think it will happen, yet. Apple, right or wrong, goes for a “refined” streaming product that is virtually all original content. The content style will play well to a certain group of limited viewers but not to the wide masses, unlike Netflix. This certain group will pay for AppleTV+. Ads will get them little subs without buying content or catalog of entertainment.
Another reason why, Apple has the Hanks-Spielberg 10 part World War 2 series that should be announced extremely soon. This is a quarter billion dollar production and it will appeal to the masses. The first ww2 series from hanks and Spielberg, band of brothers, garnered over 10 million subs for HBO in 2001, Another 4 million subs for hbo for the second series, the pacific in 2011. Now with streaming popular I’d expect the third series, Masters of the Air, to easily get 10 million paying subscribers added for the 10 weeks of episode. Nothing will happen before that is played.
If ad supported is the way, why haven’t they done it with Apple Music?