The results of Seattle area companies beg to differ. I live in Seattle and I find that if I walk outdoors during the day at least once per day, I'm fine.
Tech companies can only produce what their employees output. If people were so miserable in Seattle there's no way that any company based there would thrive enough to be a top company in the world.
There are successful companies that eat their workers alive, employee happiness isn't related with their success in a lot of cases.