...but why the hell I feel this? I'm happy for those guys and for the music they are able to make. It's awesome. I hate selfish thinking and I'm not in this for fame or money. Yet these thoughts appeared and bugged me for few days. I'm confused.
Here are my two euro cents: it's easy to underestimate your own skills when you're at a high skill level (the Dunning-Kruger effect). On the other hand, it's also very easy to overestimate the skills of others compared to yours. When you think about your skills, you weigh in both what you can do and what you can't. But from others you only hear what they are good at, not their limitations, so you have a biased view.
As a personal anecdote, I have definitely been there, mostly regarding playing the guitar. Whenever I meet a guy who can play jazz, I feel like I suck, because I just can't play jazz at all. But the truth is, I'm pretty good at playing metal, and chances are that that person would feel the same way if they heard me play, just because they don't know how to play metal!