There are a lot of people out there with PhDs that probably don't deserve them. On the other hand, we are in a system where the primary metric used to determine the completeness of a PhD is number of completed research publications (or other equivalent markers of completed research). Unfortunately scientific research is not always within our control - while your own personal attributes certainly have something to do with it, failure can also be laid at the feet of bad advisors or the fact that a lot of times research just doesn't work. Strictly speaking, a PhD (at least, from my perspective) is supposed to reflect a certain high level of book knowledge, laboratory techniques mastery, and - most important - critical thinking and communication skills. In this regard a strong publication record is probably correlated to mastery of these skills, but not perfectly so. It is certainly possible to have a high degree of training in all these areas and simply not have the publication record to go along with it. In my view such people deserve their PhDs despite few if any research papers. I have also personally known a number of scientists who emerged from their PhD work with impressive publication records who couldn't think their way out of a cardboard box. (And to complete the spectrum, I've known people who graduated with PhDs and had no papers, were lazy, couldn't write for s#*$, and wouldn't be able to design a scientific research program to save their lives, so...).
The unfortunate truth is that publication record is going to be one of the first things many prospective employers (including post-doc mentor) are going to be looking at as an indicator of the quality of your degree. Especially true in academic and research circles. On the other hand, if you're using your PhD as a springboard toward alternative scientific (and non-scientific) careers, publication record will be less important, as employers will view a PhD more as an indicator of critical thinking skills rather than your ability to complete a basic research project. So while your lack of publication record will probably impact your possible employment choices, the lack of success at your research efforts shouldn't necessarily be viewed as synonymous with failure or a sham degree.
My candid opinion is that you're being absolutely foolish and making a rash decision out of pride, resentment frustration, fear, or some equally negative emotion - and making big decisions based on any emotion is a bad idea, period. You should get the highest degree the university is willing to award you - based on THEIR criteria and not your own. What will be interpreted as failure by just about anyone is quitting after several years and getting nothing. You have nothing to lose and everything to gain by getting your degree. Dig yourself out of your funk, publish the best thesis you can based on what you have, get your name on what publications deserve it, and move on with your life - whether it's in science or not. If you do all these things to the best of your ability and with a good attitude, your advisor if he/she is honorable should write you a good letter, and you'll have more opportunities than if you just childishly throw your hands up and quit.