The problem with that reasoning is, it's not like Google is rolling a percentile die. They shut down projects that don't pay stockholder dividends, no matter how popular or widely used those projects are. So...
"shut down" seems a little strong since it was replaced with Youtube Music. For most users it was a UI change but otherwise they didn't even notice. This is very different from other products that were actually shut down where they just turned them off.
I had purchased music from them, none of which is now available to me, apart from what I downloaded.