That's not so surprising to me, in that a degree tends to be an entry to a career. And that career can be long enough that competencies are likely to change in unpredictable ways over your career. So, it makes some sense for graduate employers to be more interested in an education they believe means you are likely adapt well to those changes, and perhaps lead those changes. Rather than a competency certification that shows you know the current state-of-play.
Whether that will change over time is an interesting question. If the market does move towards just certifying competencies, I have an awkward suspicion that it will be because of general trends towards workforce casualisation. If you see employees as disposable (hire the skills of today, and tomorrow fire them to hire the skills of tomorrow) then education is less important than today's competency.
This isn't intended as a criticism of MOOCs, nor in any sense to diminish them. I'm not only interested in them, but trying to develop some -- I have something of a vested interest towards MOOCs... It's just that I'm personally more interested in how we can improve MOOCs to offer an education, rather than how we can get the market to stop demanding an education and just want a competency-certification.
By competency, I don't mean some narrow technical expertise, but whatever skills it is that an employer needs their workforce to have, that universities claim to impart.
I realise that degree-certification-bodies isn't what you meant by "certification" -- that you're thinking more of the "industry cert" model, where a training centre teaches you material, and then you pay to take an exam from the certifier. The point though is that's not what society (or at least as represented by government) wants university to be. It is, at least currently, supposed to be education not just training and testing.