We know Apple is launching its subscription music service today. It starts June 30 and costs $9.99 a month after a free 3-month trial. A family plan for up to six people costs $14.99 a month.

It’s pretty much a new version of the old Beats Music service, with interesting extras like temporary exclusives from big-name artists, and a radio service with celebrity DJs. There’s a 24-hour station called Beats 1 that’s hosted by DJ Zane Lowe.

Here’s what we don’t know, which is the only thing that matters: Is all of that better than free?

Because here’s the thing about subscription music services: They’re all the same. Each of them sells, more or less, the same music, with the same basic premise: Give us $10 a month, and we’ll let you rent all the songs you want, whenever you want them, wherever you want to hear them.

The one big exception to the rule is Spotify, which also offers a 100 percent free version in addition to its $10-a-month version. The premise is that many people who try the free version, which comes with ads and limited access on mobile devices, will eventually switch to the paid version, which is ad-free and offers full access to mobile users.

And don’t be confused: It’s that business model — not Spotify’s technology, or social hooks, or bells and whistles like playlists for runners — that has given Spotify a huge lead on everyone else. Spotify says it has at least 60 million users, and has convinced 15 million of them to pay. No one else is even close.

For Pandora, which has both a free and paid music service (though you can’t choose songs in either), the vast majority of its 79 million monthly users are listening to the free version, more proof people prefer music that doesn’t cost money.

Apple insists that free music — at least, free, unlimited music on demand — is a bad idea, and says music “needs to get behind a paywall.” The CEOs of the big music labels, who have decided that Spotify, as well as YouTube, make too much money giving their tunes away, agree.

But insisting that people pay for music won’t make people pay for music. Especially when you’re asking them to pay $120 a year for music — much, much more than music fans ever paid in the good old days of the CD era.

But wait a minute! Paid music services are still a new idea to most people around the world. And Apple has 800 million credit cards on file and a ton of market muscle at its disposal. Won’t that change everything??

Maybe! But if muscle were all it took to get people to adopt a music service, then you would be a regular user of iTunes Match and iTunes Radio.

And while the new team that Apple acquired in its $3 billion Beats deal may have helped the company create something pretty special, that’s not a foregone conclusion. After all, these are the same guys who (presumably) thought that shoving a new U2 album onto everyone’s phone was an awesome idea.

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But what about those exclusives? What if Apple manages to get its hands on music before anyone else does? That’s a big deal, right?

Hard to imagine it will be. Apple will almost certainly get some new releases for big-name artists before other people. But exclusives aren’t a new idea. And they don’t last long. Because while the music labels that own the music are happy to give a distributor a short-term boost in exchange for a check, they want to make sure they can sell their stuff in as many places as possible.

And for just about every big artist except Taylor Swift, it’s the music labels that get to make that call. That’s why Beyonce’s music is available on Spotify and everywhere else, even though she’s married to Jay-Z, who sure would like to have some exclusive stuff on his Tidal music service.

You can see why the music industry, beleaguered since 1999, would be so hopeful about Apple’s launch today. “It’s the beginning of an amazing moment for our industry,” Sony Music boss Doug Morris wished out loud this weekend

But remember that when the iTunes store launched way back in 2003, it changed the core premise of the music business — $1 singles instead of $15 bundles. Today, Apple is giving people the same deal they can get somewhere else. Tim Cook’s version will have to be pretty amazing to move the needle.