Google is, if nothing else, obsessed with metrics; unless they'd A/B/... tested this to death, there is zero chance they'll roll it out to their homepage.
I can't believe it, and it's not mentioned anywhere on their blog post.
To be fair, most people probably search from the chrome toolbar now, but even so, I imagine at most, we'll see a staged roll out to a cohort to test it.
Rarely do I see them searching using the url box. That's where web addresses go silly!
All companies that design to metrics instead of vision always ship the worst UI/UX crimes. This is the ideology we have to thank for things like the lightbox sign up forms that block or lock out content if you try to browse without an account on FB/Pintrest etc.
You're assuming the metric Google is designing for is still how fast a user gets what they want off site. What if the metric they're designing for is how long someone spends in the Google ecosystem?