It's more that we are so absurdly petty, pathetic, and entitled that we refuse a tiny, minuscule amount of pain for the greater good. Maybe back in 2010 the difference in speed between the browsers mattered but I've used Firefox since version two and as long as you had an ad blocker the speed was NEVER an issue.

So now we've given a hostile ad agency control of the internet to save 100ms on certain web site loads. Good job everyone.