Ask HN: Why don't the current startups looks like Google's 1999 video?

I was watching Google's Friday meeting video: http://www.youtube.com/watch?v=u68QWfHOYhY&feature=player_embedded

Just wondering why do the current startups don't look like in the above video where everyone - young, old, men, women, babies, dogs etc all working together? The current startups all look the same with all men in their early 20s. Sometimes maybe there is one woman doing office work.

What have changed now than 10 years ago? Why don't we see more diverse people at startups these days?