If I can repeat back to you what I just read, I heard "I see other people finishing things, and I can't finish anything. How can I finish things?"
No snark intended at all -- I'm in the same boat! -- but the solution seems patently obvious: finish something, anything. It really just comes down to perseverance.
The beginning of a project is really really fun. It's setting things up, it's exploring new technology, it's trying new ideas to see what works. But the closer you get to the end, the more tedious it gets. It's harder to find fun in integration testing and making sure this button is pixel perfect and this API is returning the right fields and running migrations with no downtime.
At your job, this seems like a reasonable list of things to do, but that's for a few reasons. One, you're being paid to do it, and two, it's literally your job to do it and you don't have much choice. But for side projects? Why write dozens of integration tests when there's a shiny new project over there that looks fun?
So to reiterate, the solution is to finish something. Finish it. Put it out there. Then and only then move on to the next thing.
All of that said, you are also missing some less concrete components of these people that you admire. Maybe they're hyper-fixating. Maybe they're using coding as an escape from something in life. Maybe they find those integration tests really, really fun! Also, some of these people are truly experts in some areas that seem esoteric and complex to you. I have a number of friends that have PhDs in particular topics and they don't know how to dumb things down for the layperson. To them, quantum physics is as easy as basic algebra is to you and me! Phil Eaton, for example, can write a lexer blindfolded with one hand behind his back -- he's written dozens of lexers! I've written a couple, and I still stumble through each one. But I can run 10 miles on a dime!
It's worth remembering that prolificness doesn't mean anything other than they're prolific. It doesn't mean you're not good, it doesn't mean they're amazing. It just means they're prolific.
Hope that helps. :)
