The indignation in this thread and from OP is ridiculous, especially when all the ire is aimed at Firefox, who are doing the same thing all browser makers do.

The indignation in this thread and from OP is ridiculous, especially when all the ire is aimed at Firefox, who are doing the same thing all browser makers do. When you are changing the very fabric of the whole web, rolling things out in a gradual, controlled way is paramount. Not just because people can find and report issues before roll-out reaches 100%, but also because browsers collect telemetry on features and how they work in the wild that can be used to gauge the effect.