I have been dealing with similar issues. Never been successful at anything I have done and I began programming later than you did, with C. I did run after a lot of tech, new toys etc. Even though it is nice and many times important to know the new and emerging stuff, I accepted that it overwhelmed me and I have to narrow down a bit. So, I started learning a (only one) new language and chose Python because it seemed easier to focus of the task at hand with Python and not get drowned in gory details of the tool.

I figured that I will work on what I like rather than what is or will be 'cool' after 4 years of this struggle. There were humanitarian projects I had thought of as a junior in college that never saw the light of day. I have begun those. It makes me happy to work on things that I want to work on, rather than what can become a great business. At least that's a start. I have started thinking in terms of how can I deliver a great product to my users from the idea I have and love.

Don't get me wrong, I am still learning. I have to make a mental note every hour of the day to not compare, not get distracted. My physical therapist told me that one has to make a mental note of their posture. That is termed as "body mechanics". I think that that goes with our minds too. You have to keep training yourself to stay positive by little tricks like avoiding comparison, recognizing what you want to do and accepting reality etc.

Maybe not the best advice but my 2 cents.

Good luck!