There's a famous anecdote about the famous science fiction editor John Campbell meeting a fan of his magazine. When the fan mentioned that he'd written some stories, Campbell remarked that he didn't recall seeing any submissions under this fan's name. "Oh, no," the fan remarked. "I haven't submitted them to you because they're nowhere near good enough for that." That's when Campbell exploded and said, "How dare you reject stories for my magazine! You submit the stories to me and I'll decide whether they're good or not."
Even if you don't want to apply and endure the ignominy of being bounced, (though you should just grit your teeth and get bounced; you'll get over it, and "getting over it" is a skill worth practicing!) I'd encourage you to take a current or former employee of Valve out for coffee some day and ask what it would take for you to get a job there. Have a five-minute chat. You might learn something, and you might even be surprised. One of the points that the OP makes is that it's really easy to make a mistake in evaluating your own depth of skill.
I am reminded of the story retold on (e.g.) this page:
http://emmalarkins.blogspot.com/2008_08_01_archive.html
There's a famous anecdote about the famous science fiction editor John Campbell meeting a fan of his magazine. When the fan mentioned that he'd written some stories, Campbell remarked that he didn't recall seeing any submissions under this fan's name. "Oh, no," the fan remarked. "I haven't submitted them to you because they're nowhere near good enough for that." That's when Campbell exploded and said, "How dare you reject stories for my magazine! You submit the stories to me and I'll decide whether they're good or not."
Even if you don't want to apply and endure the ignominy of being bounced, (though you should just grit your teeth and get bounced; you'll get over it, and "getting over it" is a skill worth practicing!) I'd encourage you to take a current or former employee of Valve out for coffee some day and ask what it would take for you to get a job there. Have a five-minute chat. You might learn something, and you might even be surprised. One of the points that the OP makes is that it's really easy to make a mistake in evaluating your own depth of skill.