The recommendation changed from car lengths to seconds decades ago, but wasn't well communicated fwict. I learned car lengths from my dad and then seconds when I got my motorcycle endorsement.
If everyone were leaving 2 seconds of space, it also reduces stop and go traffic that is caused, or at least exacerbated, by the traffic wave phenomenon. But that's even less well socialized.
I feel that Mozilla is making the case for the exact remedies being discussed. If they didn't have financial entanglements with Google, they might still make the same choice, to offer Google Search as the default. However, substantial sums of money are at play. That, coupled with a lack of upfront choice for users (e.g., a first-run pick list), undermines Mozilla's entire position here. It's hard to believe they would be advocating to keep Google Search as the default if those large sums of money weren't at stake.
It is also disingenuous at best to equate choices being present elsewhere (search bar drop down) with the default choice when a user hits the enter key. That part bothered me quite a bit.
I'm a daily Firefox user since before it's 1.0 release, outside of some limited attempts with Chrome and Safari over a decade ago. Mozilla's choices recently, including this defense of Google, have made me begin considering alternative browsers, even though there are so few user-respecting ones.