I've known many people who dropped out of university and basically blame the university they visited for this happening to them (too 'theoretical'...duh!. it's like 'I quit playing waterpolo because I realised I don't like getting wet). They get good jobs until they reach fourty and reach the ceiling of opportunity (at least in the Netherlands).
I see the same with certifications. I've been in the IT industry since 1990 with a background in electronics and computer science and know MANY colleagues who THINK they are pretty good, just as I do/did. However, the certifications I did show me that there was still a lot I could improve on, and they also updated me with current practices and standards, which can be very confusing in the IT-industry as everything gets hyped in this particular area. The SUN certification programmes are not overly expensive and they do not demand irrelevant things (like: which colour coding should you use when using netbeans or something equally goofy), and they do offer others a means of evaluating your current state of expertise. If your experience already has got what it takes to follow the exam, they are also easy to make. But people DO flunk them, and not only because of the sorry excuses you hear after the exam is finished, but mainly because they simply could not make them.
I've experienced years in Dutch IT where every idiot who had at one point in their life touched a keyboard could call themselves an IT-pro and got away with it, and that background and training where considered irrelevant (consider a successful job application for surgeon on the grounds that you always watch ER...) and personally I am glad that a solid background, training and keeping up-to-date have recently become more important. It is the sign of a maturing industry. Not all certifications are good and worthwhile, but the popular ones are this for good reason.
There are many good IT-professionals without certifications and bad ones who have got one, but I do think that the percentages good-bad are very different on the non-certification side and the other.

keesp