Because it costs money. An https connection requires an order of magnitude more resources to set up and maintain than a plain old http connection. Even with ha

Because it costs money. An https connection requires an order of magnitude more resources to set up and maintain than a plain old http connection. Even with hardware acceleration it takes more electricity per connection, and dedicated SSL accelerator boxes are not cheap (a pair of load-balancers with SSL acceleration will cost more than a new car). When you're operating at the scale of Google, that can add up quickly.