it's really a variant of credential inflation: raising the bar of what it takes to get the job.
i think we have to remember that these numbers are *averages*. dissagregate them and see what you get, tho you can't actually do that with bls stats. i think it'd be a good idea to dissagregate them by occuapation, however. look at those with college degrees in the kinds of fields that attract community college and chico state type studs. and then look at the college premium for other sorts of jobs.
i think that it is very wrong to claim that a chico state student is going to necessarily be making a significant amount more than a highschool grad. i don't see any reason to presume that the same gap between the classes doesn't also exist here in terms of education.
afterall, what exactly is the college premium? you know yourself that a yale degree, doug, is about having the right attitude-- the world owes you something because you are a member of a chosen people. now, you don't get that same kind of attitude at lesser colleges. you do instill the attitude that you should be earning more be/c you have that degree.
i also recall that a bernstein et al number was that 25% of college grads ended up in highschool type jobs for 5 years or more which, for them, meant that they'd been their long term and were likely to stay there. and it is also the case that the attrition rate at lower division schools is far higher. so there is *access* but not retention. so numbers of how many go on to college says little if you don't ask how many actually graduate from college. i know the numbers there show that poor and people of color have a higher attrition rate b/c they often drop out to earn money and/or drop out because they can't handle working full time and going to school fulltime.
also, one of the mainstays of working class culture was, for a long time, that a college degree bought you nothing. there are always stories circulating about how so and so without high school degree is making more than so and so who has a college degree. this was esp common in the 70s, when there were far too many college grads on the market. it has eased off as credential inflation has intensified and few people will say that a college degree isn't worth a try.