To mark ChatGPT’s third birthday, the Guardian’s Robert Booth tours Silicon Valley in search of the future: “Everyone is working all the time,” said Madhavi Sewak, a senior leader at Google DeepMind, in a recent talk. “It’s extremely intense. There doesn’t seem to be any kind of natural stopping point, and everyone is really kind of getting ground down. Even the folks who are very wealthy now … all they do is work.”