I think your approach to motivation is flawed. You're throwing yourself into a situation where you require an external motivator in order to get things done.

I think your approach to motivation is flawed. You're throwing yourself into a situation where you require an external motivator in order to get things done. Even if that works, you still haven't fixed the root problem, that you lack the internal motivation to pursue your goals. The best you can do under this system is to jump from one external motivator to the other. To develop internal motivation, force yourself to work on your projects a little bit each day. You're not going to go from zero hours to five hours a day in the space of a week. Internal motivation is like a muscle you have to develop over long periods of time. Resign yourself to the fact that you don't have the discipline to live up to your expectations right now, but eventually you will if you push yourself a tiny bit more each day. As Epictetus once said, nothing great is produced suddenly. To actually answer your question, no you shouldn't go for a PhD, since it's not an external motivator, it's an anti-motivator. When I started my doctorate I wanted nothing more than to be in graduate school doing research. I would have been satisfied to spend the rest of my life being a graduate student, if only I could continue my work. By the time I finished I was drinking three nights a week, and wanted nothing more than a chance to go back in time and convince myself not to go to graduate school.