I was a seventh year associate at a Silicon Valley law firm when I left for my startup in 2014. At that time, my rate was $600/hr. I'm sure there are cheaper firms out there, but I'm also sure that rates have gone up in the last 6 years. The figures he quotes for the lawyers that were used ($1,200 for partner, $900 for senior associate, etc.) are about what I would expect legal fees to be at a first- or second- tier firm in Silicon Valley these days.
Perhaps the $450 number is based on nationwide averages — but if so that's not really relevant to the cost of Silicon Valley lawyers. I know I wouldn't hire a lawyer around here who has 10 years of experience and charges only $450/hr.
I'm not quibbling with the major thrust of the article (I'm a startup founder, so I'm all in favor of VCs covering their own legal fees). But when I read the stat above, it made me suspicious because it is so far off from my experience.