I'd garner to say the difference between Valve and Google would be their size. Valve (according to wiki) has ~260 employees. I'm sure Google has more janitors than that. As I'm assuming very few people leave a position at Valve, that must mean they're very very very*9000 particular about hiring, much more so than google is.
Nobody said that they're the same today. The parent claimed that Valve and Google's work environment were the same (at Google's early onset) and wondered why "Google's ended up blowing up". My answer to that question is that Valve was able to keep the culture they have because they kept the company size small, and Google was unable to sustain that culture because they exploded in size. If Valve were to start hiring like crazy (as Google did), you'll see the same thing happen. I believe strongly in the culture that Valve promotes in their company, but I don't believe it can survive a mass influx of hiring.
