Pivotal is a for-profit company. We pair program because we think it's more effective for most engineering activities (not all: most) than soloing.
I'm vastly more productive in a pair. I don't take 3 hour "5 minute" Facebook breaks. If I get stuck, my pair usually has an idea, so rather than spending a day fighting I spend minutes. Usually the discussion with a pair comes to a better design, sooner, than nutting it out by myself. Working with a pair makes me accountable -- I am far less tempted to take shortcuts with tests, code, readability, design or other important properties.
Many folk will say well gosh, they don't need a pair for these things. I envy you, brave superhuman. I have ADHD and the crippling disability of being merely mortal, so pairing is awesome for me.