So what? Who cares what the statistics say? I still buy CDs and will never use Itunes with their crappy quality, I rip my CDs in FLAC format with bitrates over 1000kbps, who needs Itunes 200-something bitrate. Or I listen to my CDs on my Stereo. I still have a normal newspaper and so do millions of people.
The publishers care what statistics say. They want to know where the money is.
Either that or another company will purchase it and systematically sell off it's assets for profit. Either way this "plan" will probably never see the light of day, leaving all of it's users high and dry.
Another company would purchase it and most likely continue operations. Steam is a cash cow. I know Microsoft personally wants it, because GFWL is weak in comparison but they refuse to give up their plans of controlling the PC gaming market like they do Xbox.
But I do trust Valve. They seem to be morally good, unlike companies like Activision, and really take care of their players. If they cared so much about just making money, I don't think they'd give their games away for free like they do once in a while. I have two wonderful licenses for Portal and one for Half-Life 2, neither of which I paid for. In the event Valve goes under, I am confident that they would send out a patch that removed the lock-in for Steam games. Perhaps trade the licenses to the last surviving digital distributor.
Also going on this though, I don't forsee Steam ever going under. That isn't to say it's impossible, but the trend of going digital is very real and is happening now. This is why I have Netflix, I don't go to Blockbuster anymore. The Blockbuster in the town over just closed its doors because it isn't earning money anymore. I used to work at Target, and the CD section keeps shrinking every year to only include popular artists, ones that will still sell. I read my news online and watch it on TV, I don't have a newspaper. And while I prefer physical books, I've bought a few Kindle versions because it saved me a drive to the bookstore. Not everyone does this, but the majority does, and that's what matters in the end