That's all well and true but honestly, how many currently unprofitable sites would become monstrously profitable if they could increase their requests per second by a factor of 5?

The study you link to shows a decrease of in rev of 5% by adding 2 seconds of load time vs. 50 ms. There are very few businesses whose costs are dominated by servers. Most spend more on a single developer than servers. Yes, Google, Twitter, and Facebook could probably do well by doubling their requests per second but the average companies costs are dominated by employees, that why it's called Ramen profitable and not EC2 Micro profitable.