But the probability of life arising is an unknown. Intuitively I too feel it probably isn't that small, but it wouldn't be the first time intuition about the universe is wrong. How do you _know_ the odds of life arising aren't 1/10^30?
Disclaimer: I'm the one who made the change in [1] so I'm biased but...
IMHO the argument on the blog mischaracterizes the situation - Chrome didn't break these properties but changed how they're interpreted under pinch-zoom. This was done precisely to keep backwards compatibility (on desktop browsers): at the time, the vast majority of pages assumed pinch-zoom can't happen on desktop (something that was becoming more common). The status quo meant zooming in on a desktop page would cause it to "swim" as various "fixed" elements shifted around, JS drop-down menus appeared in the wrong place, etc. This happened virtually everywhere one looked: facebook, twitter, apple.com, etc.
The blog basically argues for "make pages fix themselves" which, even if major sites do, is unrealistic in the long tail.
> They might pull the “proposal” only to just do it again later
It's not nefarious, this often happens in response to feedback and real world experience to try and minimize disruption. In this case, developers convincingly argued that there should be an API to better react to pinch-zoom before making the change.