1/3, and I dropped out of it because it wasn't teaching me (or any of the other people I met there, including those who didn't have my prior experience) anything - I got a first in the first-year exams if that's the kind of thing you care about. Absolute best case is that that degree has two years of useful content, and I rather doubt it.
When I was in university doing a CS degree, if you had dropped out 1/3rd of the way through, you'd have pretty much only gone through a handful of weeder intro CS courses that were more math than programming. So yes, if you had dropped out at that point, you would not have really gained any useful programming skills.
I don't entirely disagree with you, there were certainly some later classes that were similarly not useful in the long run, but it wasn't a total crapshoot. My senior year included a year-long group project on a team of ~10 people that basically took us all the way through the lifecycle of a project -- from inception, to design and architecture, to polish and QA, to 'releasing' it. It was a very useful course that placed you into a startup-like atmosphere.
But I think this kind of confirms that apprenticeships may be far more useful to the programming field than college degrees. If my CS program did not include that senior course, I would probably pretty vehemently agree with you. And anecdotally, at my current workplace, one of our best programmers is a kid we hired basically right out of high school who has since grown in skill considerably thanks to the attention of more senior engineers.
