We often hear comments from people that have put hundreds of hours into learning SEO and comparing it to a couple of hours of study in PPC. Both disciplines take time and resources to learn and master.
If you are having difficulty making PPC work for you then it could be for many reasons, one of the most common is lack of skill. Search engines are very good at providing relevant results for searchers, so the search engines are handling the targeting of your traffic in organic results. With PPC you are in control of your targeting methods, so if you lack the skills and knowledge to properly target your audience you are likely to fail.
Perhaps it isn’t PPC that has failed you, but you that has failed to put in the effort to learn how to master PPC?
Have you taken courses, coaching, or hired consultants? How in-depth has your study of PPC been?