As the music industry’s business plan continues to be torn to shreds, the big question—the only question—is what comes next. Is a subscription model the answer? Should the industry just throw in the towel and say hey, let’s try to get people to voluntarily give us some money every month, so at least we all won’t starve?

That’s what the new head of Columbia Records thinks. His name is Rick Rubin:

Rubin has a bigger idea. To combat the devastating impact of file sharing, he, like others in the music business (Doug Morris and Jimmy Iovine at Universal, for instance), says that the future of the industry is a subscription model, much like paid cable on a television set. “You would subscribe to music,” Rubin explained, as he settled on the velvet couch in his library. “You’d pay, say, $19.95 a month, and the music will come anywhere you’d like. In this new world, there will be a virtual library that will be accessible from your car, from your cellphone, from your computer, from your television. Anywhere. The iPod will be obsolete, but there would be a Walkman-like device you could plug into speakers at home. You’ll say, ‘Today I want to listen to … Simon and Garfunkel,’ and there they are. The service can have demos, bootlegs, concerts, whatever context the artist wants to put out. And once that model is put into place, the industry will grow 10 times the size it is now.”

From Napster to the iPod, the music business has been wrong about how much it can dictate to its audience. “Steve Jobs understood Napster better than the record business did,” David Geffen told me. “IPods made it easy for people to share music, and Apple took a big percentage of the business that once belonged to the record companies. The subscription model is the only way to save the music business. If music is easily available at a price of five or six dollars a month, then nobody will steal it.”

That’s from a profile of Rubin by Lynn Hirshberg in the New York Times magazine as he settles into his new job at Columbia. This is an easy issue to make fun of, starting with the vast differences in the rates envisioned by Mssrs. Rubin and Geffen. But I can’t imagine this ever happening because of the restrictions that companies would put on it. The whole package would be DRM’ed within an inch of its life, and the industry would have to continue to sue downloaders and anyone who even thought about hacking the subscription service. (Indeed, I would envision the RIAA getting a law passed making it illegal to make any sort of copy of the music you subscribe to.) And, as is the case with Rhapsody-style services, you would presumably lose all the music and your playlists when you let your subscription lapse.

Distributing the funds would be very hard as well. The sensible way to do it would be simply to monitor what songs consumers actually play or listen to, but that raises obvious privacy issues. (And logistical ones; I’m sure I’m not the only person who leaves his iTunes playing music on the computer all day long, whether I’m at the computer or not. )

How the numbers would crunch is hard to get your mind around, even if all the logistical and legal and technical deals could be finessed. Split the difference between Geffen and Rubin’s numbers, say $12 a month. If the U.S. CD-selling biz is in very crude terms a $5 billion annual affair, you’d need a good chunk of the country, 35 million people, shelling out $144 a year. I don’t see how that works, particularly since we’re really talking about households, not individual people.