Recently, I've been struggling with this issue. I really really love theoretical physics and mathematics, but at some point, I feel like it has now become into a mix of speculation and super advanced mathematics. The fact that some physicists say some areas like String Theory or Quantum Loop Gravity are overpopulated sound to me like crazy: Can a "theory of everything" be overpopulated? what if that theory is right? Theoretical Physics, in my very own perspective, is biased into the theory seems more reasonable, more "explainatory"... and then, when it's theorized enough, you switch into another theory, and then again and again the same thing... It's like you're doing nothing with your life! The thing is that I love it despite all this, which is my very own perspective. But then there's Artificial Intelligence, which seems to be the future in all ways, and it's intellectually challenging too. The salary is way much higher than physics (in some parts of US, the average salary is 140K$ per year, whereas in Physics you're lucky if you get to 100K). Now there's the problem that it doesn't sound to me that interesting. I mean, it's interesting to delve into what is intelligence, creativity..., the algorithms that would fit better into reasoning... but if we compare that to Physics, Physics is like the cool, crazy stuff. Am I right? Should I give up the cool, interesting stuff of Physics in spite of the biggest thing the human could ever create, AI? Or just stay in Physics (maybe and I just say maybe until machines take control of all this research)?