Im surprised youtube (even after absorbing now shuttered Google Play music) is largest, unless that includes video YT playback as music streaming- but hey, what do I know.
In the stats I posted it looks like it's not counting Youtube itself as a music streaming service for music and music videos. Youtube has 1.68B as in Billion users worldwide in 2019.
From the same site 2014-2019:
https://www.statista.com/statistics/986769/weekly-youtube-music-usage-population-usa/
Weekly YouTube music usage among U.S. population 2014-2019
Published by J. Clement, Apr 2, 2019
This statistic presents the percentage of weekly YouTube music usage among the population in the United States from 2014 to 2019. According to the findings, in 2014, 33 percent of the U.S. population was found to be using YouTube in any given week for either music or music videos. By 2019, half of the total U.S. population used the video website for music consumption on a weekly basis.
Yeah, so that's like...160Million people per week in the US alone.