Earlier quoted context omitted.
Notably, Mikolev is now at Facebook. My hunch (as a total outsider) is that anything Google publishes is about 2 years behind their current best practices.
The back-and-forth on the ImageNet record between Google/Facebook/Baidu suggests that, unless they're exquisitely coordinating research release, at least some of what they're releasing is indeed close to their state of the art . obviously writing it up does mean the specified results will be a bit behind what they can actually do in their labs, but that's true of everywhere
As an example model, imagine all three are years ahead of published material, and each has policies that encourage publishing only the minimum necessary to "take the crown" (because any more would risk diluting proprietary advantages).
That'd result in the observed back-and-forth, and – given lead-times on paper-writing, internal review, and marquee conferences – it wouldn't necessarily force an acceleration of the "published state-of-the-art" up to the level of all of their "internal states-of-the-art". (Perhaps, for a group in trailing/catch-up position, their published results will be very close to their best. But the leader could be arbitrarily further ahead.)
By analogy to English auction bidding: outsiders only learn the second-highest reserve price just before the end, and never learn the winner's true reserve price. But here there's no end, and there's always potential competitive reasons for the top-N pack to hide some of their leading-edge practices.
This doesn't require explicit coordination… but there could be explicit coordination, too! All the programs are staffed by former students/colleagues/coworkers of each other.