It won't let me edit, but I realized my comment is not clearly worded. You, as a listener, would have to listen to more than fifty thousand streams in one month to "pay" Google an amount of ad revenue equivalent to the Google Music monthly subscription rate. So unless you listen to more than 1500 YouTube tracks per day, you're better off paying (if your goal is to support the artist).

There's just not enough money in ads. This is why things like Patreon exist.