why can't I preview a song without an Apple Music subscription

Thanks for the extra details! It sounds like you need to enable iTunes Store on Music. Try this:

1. Open Music
2. Click Music on the menu bar > Preferences > General > the box next to iTunes Store

Then, you can browse the iTunes Store by selecting it from the sidebar in Music, under 'Store'. :)

I know I can preview the music on genius, or Amazon music, or probably Youtube. The point is that if Apple wants to sell music, I shouldn't have to go to another app to preview what I'm thinking about buying. The preview doesn't always work anymore if you don't have a subscription, and I don't want a subscription.

I am having the same problem and this suggestion did not help.

I can listen to music previews on older albums and songs, but when I try to hear a preview for a song that was released in the last month, nothing plays.

Note that this is the Music for iOS forum. In case anyone reading this has an iPhone, and gets confused by the description of where things are on a Mac:

• On a Mac, the iTunes Store is located within the iTunes application (pre-Catalina) or the Music application.
• On an iPhone, iPad, or iPod Touch, the iTunes Store has its own app, separate from the Music app.

See iTunes - Official Apple Support

Use Feedback - Apple Music - Apple to vent. Good luck!

Apple Music isn’t for purchasing music, it’s for subscription streaming. Use iTunes for that.

Nope! You can access the iTunes Store using the link you described within the Music app. :)

Try genius for previews https://genius.com/, no fuss, all song.