It stopped being listed as having guaranteed updates but it already has gotten at least one more update since then. Per https://developers.google.com/android/im

It stopped being listed as having guaranteed updates but it already has gotten at least one more update since then. Per https://developers.google.com/android/images#sailfish https://developers.google.com/android/images#sailfish there's been an update for the Pixel in December 2019. It is missing the Jan & Feb 2020 updates that the Pixel 2 received, but it's plausible the Pixel 1 could still get a patch for this critical issue.