[atopal]

Looking at browser usage for the last two major versions is misleading. That would only be true in a parallel release of a web platform feature in every browser, but that's basically never the case, and it's not the same for every feature. A feature like subgrid was launched years ago in Firefox, last year in Safari and will be launched later this year in Chromium. So, by the time it's in Baseline, it will be in two versions back for Chromium browsers, but 20+ versions back for Firefox and over a year old in Safari.