A model people like comes around, where some are even willing to pay for it, they endorse it for a while, then decide to pull the plug.
If they think everybody is just going to go out and buy the music they were listening to on spotify instead they're wrong. A lot of people using spotify like it because of the format (convenient, all under one roof), were happy that it was legal because of the ads, but were never going to go out and buy the CDs. They'll just listen to something else on the service instead. They didn't buy anything, and they're not going to buy anything. The monthly fee is tempting to get rid of the ads, without restricting their choice.
Other people, such as myself have bought several albums I've listened to on spotify, while they were still available on spotify. It didn't matter that I could listen to them for free, I like the concept of physical ownership and being able to store my own local FLAC copies of the discs I own, to convert on demand for my MP3 player etc. For me, spotify is/was a nice way to be able to preview some albums, without having to resort to illegal means, it resulted in actual physical sales for albums I deemed good enough, of which there were plenty.
It might not be what Warner want to see, but the true value of their music is far better reflected by business models like Spotify (wihch is really just a personal radio station) than the prices they'd like to charge for their lossy compressed files. They're obviously afraid of this becoming the accepted value, but it's inevitable anyway and all they're going to achieve by pulling the plug is driving people back to torrents etc. It's as if they've seen the future, and decided they don't like it, and still somehow think they can change it.
Give people a reason to buy your products and they will. I quite happily just paid ~£27 for the deluxe edition of David Ford's new album, there's nothing special about it over the standard one, it's the exact same CD, but I'm paying the money for the physical product.
Really, need a 'pulling hair out' icon here, sometimes it's hard to believe that the people making these decisions miss the obvious.