I was going to post this if somebody else didn't. To add one important detail: the HP Stream you linked doesn't just exist as a proof of concept or whatever, which would be one thing, but it's currently outselling all the Chromebooks (and every other laptop for that matter) on Amazon.

Chromebooks dominated in 2014, but they've been bumped and I'm not sure they'll ever be back at the top. Rather than a sea change, it looks like Google was just ahead of its competitors for a year, and now that year has come and gone.