Traditional publishing houses aren't going anywhere because they're absolutely and fundamentally necessary to the quality of the books you read, regardless of the means of delivery. There are always people who will manage without, but they are very much the exception. Without publishers, we'd be swimming in an endless sea of junk. We need them to figure out what the good stuff is. Really. Daithi is right to think of them as 'gatekeepers', but the problem with people rating stuff outside of that traditional mechanism is that they're likely to get very tired very quickly of trying to rate stuff that's really bad, and there's a lot of it out there. Way, way, way more than there is of the good stuff.
Even if such a thing happened, people would cry out, 'we need somebody to sort the rare slivers of gold out of this endless sea of kak!' And lo, they would be called Publishers.
On the other hand, you might want to check out
www.authonomy.com, recently launched in beta by harper collins in the UK. You can read about it on a website called The Digitalist, run by Pan Macmillan, and which focuses on electronic publishing issues (I've written for them myself):
http://thedigitalist.net/?p=215
You currently apparently need an invite to get into authonomy, but the idea appears to be that people can upload their manuscripts and get other people to rate them. The highest rated ones get to the attention of the editorial team. If you think they're just being lazy, you should know the average major publisher receives, I think, on the order of several hundred unsolicited (ie unagented) manuscripts
every single week.
But it is, nonetheless, an interesting move; you upload your unpublished novel or sample chapters (apparently they have some system for avoiding plagiarism), let other people read and rate it, and do the same for them. At the very least it's an interesting experiment, and in the direction of what some people here have been talking about.