I don't think traditional VC firms are competing with YC at all.
There are two "black holes" in venture capital right now. One black hole is YC + angel investment. When you're getting started, it's pretty much standard practice to go through YC and/or raise seed capital from angels to get your startup off the ground.
The other black hole are a few top VC firms (off the top of my head, a16z and Sequoia). These firms pretty much figured out that it's impossible to predict success, so they're putting large amounts of capital into companies that are already succeeding. They've essentially eliminated guessing; they can get away with it because they established themselves as the VC firms you go to if your company is succeeding (so they have no issues with deal flow).
Then there are traditional VC firms in the middle, who can actually operate by perpetually losing money due to a slightly weird wider financial climate and the incentives of their LPs (see http://pmarchive.com/truth_about_vcs_part1.html, http://pmarchive.com/truth_about_vcs_part2.html, http://pmarchive.com/truth_about_vcs_part3.html).
So everything is much more complicated (and much more interesting) than the original post would lead you to believe!