Bret is even more impressive since he combines hardware, software and UI skills.
Why depressive? As Neal Stephenson mentions upon Hiro meeting Raven in Snow Crash. If you are over age of 25, you realize that there are certain levels of excellence that you will never reach even if you move to that Shaolin monastery.
I think some people have this innate drive to excellence (how much of that is acquired and how much is inherited is another discussion) and apply themselves with full dedication. You can see Bret's teenage projects were already pretty impressive.
Ever since then Bret's toolbox of skills has only multiplied till you see the effect today.
Try looking at things another way—he's generously provided us all with an incredible foundation upon which to build our own things. After having read a few of his essays, I certainly feel changed.
Building off of your own creations and 750¢ will get you a cup of coffee. Build off other people's creations where you can. If you're doing something different from the crowd, sooner or later you'll get to a point where you have to pull yourself up by your bootstraps, and you have to be able to do that or you'll hit a wall. But it's far from sufficient.
Or, it's like playing Starcraft agains a good player. You get beaten pretty hard but you still played your best and are proud. But then, somehow, you play a real professional gamer.. and you just feel like stopping playing that game. Nothing works, you look like a total beginner, you get 5/0-ed, and then, you learn he was on the phone the whole time.
Meh.