Two things though:
1. I used to work on Google Analytics, and I've created a lot of open source libraries around Google Analytics, which I use on my own site because I like to test my own libraries (and feel any pain they may be causing). The way most people use Google Analytics does not block for nearly this long.
2. I've updated my Google Analytics libraries to take advantage of this strategy [1], and I'm working with some of my old teams internally to see if they can bake it in to GA's core analytics.js library, because I strongly believe that analytics code should never degrade the user experience.