It doesn't sound like anyone is really 'hungry' for success at this company. Is the source of funding from this Co-Founder not limited in any way? Are you being paid?

Sometimes the best thing to do before just walking away is to set some goals with very clear expectation and consequences. One of those consequences can be that you will leave. This way, if you are interested in saving your relationship with these guys you can avoid dropping it on them out of nowhere. Who knows, maybe they'll turn around. But I can feel your frustrations. It's no fun babysitting co-workers.